package main

import compiler_core "./compiler"
import "./compiler/ast"
import "./compiler/backend"
import "./compiler/cimport"
import "./compiler/checker"
import "./compiler/hir"
import "./compiler/ir"
import "./compiler/lexer"
import "./compiler/linker"
import "./compiler/loader"
import "./compiler/llvm"
import "./compiler/lower"
import "./compiler/parser"
import "./compiler/source"
import "./compiler/symbol"
import "./compiler/target"
import "./compiler/token"
import "./compiler/translatec"
import "./compiler/types"
import "core:fmt"
import "core:mem"
import "core:os"
import "core:os/os2"
import "core:strings"
import "core:testing"

@(test)
symbol_table_deduplicates_and_owns_spellings :: proc(t: ^testing.T) {
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)

	buffer := [5]byte{'a', 'l', 'p', 'h', 'a'}
	alpha := symbol.intern(&symbols, string(buffer[:]))
	duplicate := symbol.intern(&symbols, "alpha")
	beta := symbol.intern(&symbols, "beta")
	buffer[0] = 'x'

	testing.expect_value(t, alpha, duplicate)
	testing.expect(t, alpha != beta)
	testing.expect_value(t, symbol.resolve(&symbols, alpha), "alpha")
	testing.expect_value(t, symbol.resolve(&symbols, beta), "beta")
	testing.expect_value(t, symbol.intern(&symbols, ""), symbol.INVALID)
	testing.expect_value(t, symbol.resolve(&symbols, symbol.INVALID), "")
	testing.expect(t, !symbol.is_valid(symbol.INVALID))
	testing.expect(t, symbol.is_valid(alpha))
}

@(test)
compact_tokens_intern_only_identifiers_and_preserve_parser_text :: proc(t: ^testing.T) {
	text := `other :: import "../math"
value :: 42
main func() void { _ = value }
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	value_symbol := symbol.intern(&symbols, "value")
	sink_symbol := symbol.intern(&symbols, "_")
	value_count := 0
	for tok in stream.items {
		#partial switch tok.kind {
		case .Identifier:
			if tok.symbol == value_symbol {
				value_count += 1
			}
		case .Underscore:
			testing.expect_value(t, tok.symbol, sink_symbol)
		case:
			testing.expect_value(t, tok.symbol, symbol.INVALID)
		}
	}

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, value_count, 2)
	testing.expect_value(t, module.imports[0].path, "../math")
	testing.expect_value(t, module.exprs[module.globals[0].expr].integer, u64(42))
	testing.expect_value(t, module.statements[module.functions[0].body[0]].name, sink_symbol)
}

@(test)
parser_marks_only_bang_calls_as_intrinsic :: proc(t: ^testing.T) {
	text := `main func() void {
	_ = sizeof ! (i32)
	_ = sizeof(i32)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	marked := module.exprs[module.statements[module.functions[0].body[0]].expr]
	ordinary := module.exprs[module.statements[module.functions[0].body[1]].expr]
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, marked.kind, ast.Expr_Kind.Call)
	testing.expect_value(t, ordinary.kind, ast.Expr_Kind.Call)
	testing.expect(t, marked.intrinsic)
	testing.expect(t, !ordinary.intrinsic)
}

@(test)
compact_ids_reserve_invalid_values_and_preserve_layout :: proc(t: ^testing.T) {
	testing.expect_value(t, size_of(source.Span), 12)
	testing.expect_value(t, size_of(token.Token), 24)
	testing.expect(t, size_of(ast.Expr) <= 88)
	testing.expect(t, size_of(hir.Expr) <= 88)
	testing.expect(t, size_of(ir.Instruction) <= 88)
	testing.expect_value(t, size_of(types.Type), 4)

	source_index, source_ok := source.source_index(source.Source_Id(0), 1)
	testing.expect_value(t, source_index, 0)
	testing.expect(t, source_ok)
	_, source_invalid := source.source_index(source.INVALID_SOURCE, 1)
	testing.expect(t, !source_invalid)
	_, source_out_of_bounds := source.source_index(source.Source_Id(1), 1)
	testing.expect(t, !source_out_of_bounds)
	diagnostic_index, diagnostic_ok := source.diagnostic_index(source.Diagnostic_Id(0), 1)
	testing.expect_value(t, diagnostic_index, 0)
	testing.expect(t, diagnostic_ok)
	_, diagnostic_invalid := source.diagnostic_index(source.INVALID_DIAGNOSTIC, 1)
	testing.expect(t, !diagnostic_invalid)

	expr_index, expr_ok := ast.index(ast.Expr_Id(0), ast.INVALID_EXPR, 1)
	testing.expect_value(t, expr_index, 0)
	testing.expect(t, expr_ok)
	_, expr_invalid := ast.index(ast.INVALID_EXPR, ast.INVALID_EXPR, 1)
	testing.expect(t, !expr_invalid)

	function_index, function_ok := hir.index(hir.Function_Id(0), hir.INVALID_FUNCTION, 1)
	testing.expect_value(t, function_index, 0)
	testing.expect(t, function_ok)
	_, function_invalid := hir.index(hir.INVALID_FUNCTION, hir.INVALID_FUNCTION, 1)
	testing.expect(t, !function_invalid)

	instruction_index, instruction_ok := ir.index(ir.Instruction_Id(0), ir.INVALID_INSTRUCTION, 1)
	testing.expect_value(t, instruction_index, 0)
	testing.expect(t, instruction_ok)
	_, instruction_invalid := ir.index(ir.INVALID_INSTRUCTION, ir.INVALID_INSTRUCTION, 1)
	testing.expect(t, !instruction_invalid)

	spec_index, spec_ok := checker.spec_index(checker.Spec_Id(0), 1)
	testing.expect_value(t, spec_index, 0)
	testing.expect(t, spec_ok)
	_, spec_invalid := checker.spec_index(checker.INVALID_SPEC, 1)
	testing.expect(t, !spec_invalid)

	testing.expect(t, source.fits_source_length(u64(0xffff_ffff)))
	testing.expect(t, !source.fits_source_length(u64(0x1_0000_0000)))
}

@(test)
lexer_preserves_newlines_and_skips_comments :: proc(t: ^testing.T) {
	source_file := source.Source{path="test.bro", text="# comment\nmain func() void {}\n"}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, stream.items[0].kind, token.Kind.Newline)
	testing.expect_value(t, stream.items[1].kind, token.Kind.Identifier)
}

@(test)
parser_accepts_grouped_params_and_multiline_statements :: proc(t: ^testing.T) {
	text := `sum func(a,
	b int) int {
	return (a
		+ b)
}
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(module.functions), 2)
	testing.expect_value(t, len(module.functions[0].params), 2)
}

@(test)
parser_accepts_comptime_value_params :: proc(t: ^testing.T) {
	text := `make func($N usize, value i32) i32 {
	return value
}
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	found_dollar := false
	for tok in stream.items {
		found_dollar = found_dollar || tok.kind == token.Kind.Dollar
	}

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found_dollar)
	testing.expect_value(t, len(module.functions[0].params), 2)
	testing.expect(t, module.functions[0].params[0].comptime_value)
	testing.expect(t, !module.functions[0].params[1].comptime_value)
}

@(test)
parser_accepts_comptime_type_params_and_builtin_type_args :: proc(t: ^testing.T) {
	text := `id func($T type, value T) T {
	return value
}
main func() void {
	_ = id(i32, 42)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	call := module.exprs[module.statements[module.functions[1].body[0]].expr]
	type_item, type_ok := types.node(&module.type_store, module.functions[0].params[0].type)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, module.functions[0].params[0].comptime_value)
	testing.expect_value(t, symbol.resolve(&symbols, module.functions[0].params[0].name), "T")
	testing.expect(t, type_ok)
	testing.expect_value(t, symbol.resolve(&symbols, symbol.Id(type_item.name)), "type")
	testing.expect_value(t, call.kind, ast.Expr_Kind.Call)
	testing.expect_value(t, module.exprs[call.args[0]].kind, ast.Expr_Kind.Type)
}

@(test)
parser_accepts_sentinel_many_item_pointer_types :: proc(t: ^testing.T) {
	text := `zero func(value [*;0]u8) void {}
newline func(value [*;'\n']mut u8) void {}
nullable func(value ?[*;0]u8) void {}
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	zero, zero_ok := types.node(&module.type_store, module.functions[0].params[0].type)
	newline, newline_ok := types.node(&module.type_store, module.functions[1].params[0].type)
	nullable, nullable_ok := types.node(&module.type_store, module.functions[2].params[0].type)
	nullable_child, nullable_child_ok := types.node(&module.type_store, nullable.child)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, zero_ok && zero.kind == .Pointer && zero.many && zero.has_sentinel && zero.sentinel == 0)
	testing.expect(t, newline_ok && newline.kind == .Pointer && newline.many && newline.mutable &&
	                  newline.has_sentinel && newline.sentinel == '\n')
	testing.expect(t, nullable_ok && nullable.kind == .Optional)
	testing.expect(t, nullable_child_ok && nullable_child.kind == .Pointer &&
	                  nullable_child.many && nullable_child.has_sentinel)
}

@(test)
parser_accepts_c_function_pointer_types :: proc(t: ^testing.T) {
	text := `take c_func(callback ?*c_func(value c_int) c_int) void
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	optional, optional_ok := types.node(&module.type_store, module.functions[0].params[0].type)
	pointer, pointer_ok := types.node(&module.type_store, optional.child)
	function, function_ok := types.node(&module.type_store, pointer.child)
	params := types.params_for(&module.type_store, pointer.child)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, optional_ok && optional.kind == .Optional)
	testing.expect(t, pointer_ok && pointer.kind == .Pointer && pointer.many && !pointer.mutable)
	testing.expect(t, function_ok && function.kind == .Function && function.c_abi && !function.variadic)
	testing.expect(t, function.child == types.C_INT)
	testing.expect_value(t, len(params), 1)
	testing.expect(t, params[0].type == types.C_INT)
}

@(test)
parser_accepts_native_function_pointer_types :: proc(t: ^testing.T) {
	text := `Error :: enum {
	bad
}
take func(callback ?@func(value i32) i32, fallible @func() i32 ! Error) void
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	optional, optional_ok := types.node(&module.type_store, module.functions[0].params[0].type)
	pointer, pointer_ok := types.node(&module.type_store, optional.child)
	function, function_ok := types.node(&module.type_store, pointer.child)
	params := types.params_for(&module.type_store, pointer.child)
	fallible_pointer, fallible_pointer_ok := types.node(&module.type_store, module.functions[0].params[1].type)
	fallible_function, fallible_function_ok := types.node(&module.type_store, fallible_pointer.child)
	fallible, fallible_ok := types.node(&module.type_store, fallible_function.child)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, optional_ok && optional.kind == .Optional)
	testing.expect(t, pointer_ok && pointer.kind == .Pointer && !pointer.many && !pointer.mutable)
	testing.expect(t, function_ok && function.kind == .Function && !function.c_abi && !function.variadic)
	testing.expect(t, function.child == types.I32)
	testing.expect_value(t, len(params), 1)
	testing.expect(t, params[0].type == types.I32)
	testing.expect(t, fallible_pointer_ok && fallible_pointer.kind == .Pointer && !fallible_pointer.many)
	testing.expect(t, fallible_function_ok && fallible_function.kind == .Function && !fallible_function.c_abi)
	testing.expect(t, fallible_ok && fallible.kind == .Fallible && fallible.child == types.I32)
}

@(test)
parser_accepts_c_function_pointer_alias_types :: proc(t: ^testing.T) {
	text := `callback_alias :: alias ?*c_func(value i32) i32
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	name := symbol.intern(&symbols, "callback_alias")
	alias := types.find_named(&module.type_store, 0, u32(name))
	alias_node, alias_ok := types.node(&module.type_store, alias)
	optional, optional_ok := types.node(&module.type_store, alias_node.child)
	pointer, pointer_ok := types.node(&module.type_store, optional.child)
	function, function_ok := types.node(&module.type_store, pointer.child)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, alias_ok && alias_node.kind == .Alias)
	testing.expect(t, optional_ok && optional.kind == .Optional)
	testing.expect(t, pointer_ok && pointer.kind == .Pointer)
	testing.expect(t, function_ok && function.kind == .Function && function.c_abi)
}

@(test)
parser_rejects_old_function_declaration_binding_syntax :: proc(t: ^testing.T) {
	text := `main :: func() void {}
foreign :: c_func() i32
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	found := 0
	for diagnostic in diagnostics.items {
		if strings.contains(diagnostic.message, "function declarations do not use '::'") {
			found += 1
		}
	}
	testing.expect_value(t, found, 2)
	testing.expect_value(t, len(module.functions), 2)
}

@(test)
parser_diagnoses_malformed_sentinel_pointer_types :: proc(t: ^testing.T) {
	text := `bad func(value [*0]u8) void {}
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "expected ';' after '*' in sentinel pointer type")
	}
	testing.expect(t, found)
}

@(test)
parser_accepts_single_statement_one_line_functions :: proc(t: ^testing.T) {
	text := `give func() i8 { return 7 }
main func() void { _ = give() }
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(module.functions), 2)
	testing.expect_value(t, len(module.functions[0].body), 1)
	testing.expect_value(t, len(module.functions[1].body), 1)
	testing.expect_value(t, module.statements[module.functions[0].body[0]].kind, ast.Stmt_Kind.Return)
	testing.expect_value(t, module.statements[module.functions[1].body[0]].kind, ast.Stmt_Kind.Assignment)
}

@(test)
parser_distinguishes_bodyless_declarations_and_definitions :: proc(t: ^testing.T) {
	text := `foreign c_func(value i32) i32
defined c_func(value i32) i32
{
	return value
}
native func() i32
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(module.functions), 4)
	testing.expect(t, !module.functions[0].has_body)
	testing.expect(t, module.functions[0].c_abi)
	testing.expect(t, module.functions[1].has_body)
	testing.expect(t, module.functions[1].c_abi)
	testing.expect_value(t, len(module.functions[1].body), 1)
	testing.expect(t, !module.functions[2].has_body)
	testing.expect(t, !module.functions[2].c_abi)
	testing.expect(t, module.functions[3].has_body)
}

@(test)
parser_accepts_terminal_c_variadic_markers_and_recovers_nonterminal_markers :: proc(t: ^testing.T) {
	text := `fixed c_func(value c_int, ...) c_int
zero c_func(...) void
bad c_func(..., value c_int) c_int
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	found_ellipsis := false
	for tok in stream.items {
		found_ellipsis = found_ellipsis || tok.kind == .Ellipsis
	}
	testing.expect(t, found_ellipsis)
	testing.expect(t, module.functions[0].variadic)
	testing.expect_value(t, len(module.functions[0].params), 1)
	testing.expect(t, module.functions[1].variadic)
	testing.expect_value(t, len(module.functions[1].params), 0)
	testing.expect(t, module.functions[2].variadic)
	testing.expect_value(t, len(module.functions[2].params), 1)
	testing.expect_value(t, len(diagnostics.items), 1)
	testing.expect(t, strings.contains(diagnostics.items[0].message, "final parameter"))
}

@(test)
parser_treats_c_as_contextual_only_before_func :: proc(t: ^testing.T) {
	text := `c :: 5
x :: c
foreign c_func() i32
broken :: c 5
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	c_symbol := symbol.intern(&symbols, "c")
	for tok in stream.items {
		if int(tok.span.start) < len(text) && text[int(tok.span.start):int(tok.span.end)] == "c" {
			testing.expect_value(t, tok.kind, token.Kind.Identifier)
			testing.expect_value(t, tok.symbol, c_symbol)
		}
	}
	testing.expect_value(t, len(module.globals), 3)
	testing.expect_value(t, module.exprs[module.globals[1].expr].name, c_symbol)
	testing.expect_value(t, module.exprs[module.globals[2].expr].name, c_symbol)
	testing.expect(t, module.functions[0].c_abi)
	testing.expect_value(t, len(diagnostics.items), 1)
	testing.expect(t, strings.contains(diagnostics.items[0].message, "followed by a newline"))
}

@(test)
parser_accepts_undefined_expression :: proc(t: ^testing.T) {
	text := `main func() void {
	value i32 = undefined
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	found_keyword := false
	for tok in stream.items {
		found_keyword = found_keyword || tok.kind == .Keyword_Undefined
	}
	statement := module.statements[module.functions[0].body[0]]
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found_keyword)
	testing.expect_value(t, module.exprs[statement.expr].kind, ast.Expr_Kind.Undefined)
}

@(test)
pratt_parser_preserves_left_associative_addition_shape :: proc(t: ^testing.T) {
	source_file := source.Source{path="test.bro", text="value :: 1 + 2 + 3\nmain func() void {}\n"}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	root := module.exprs[module.globals[0].expr]
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, root.kind, ast.Expr_Kind.Add)
	testing.expect_value(t, module.exprs[root.left].kind, ast.Expr_Kind.Add)
	testing.expect_value(t, module.exprs[root.right].integer, u64(3))
}

@(test)
pratt_parser_handles_prefix_negation_precedence :: proc(t: ^testing.T) {
	text := `identity func(value i8) i8 { return value }
loose :: -1 + 2
grouped :: -(1 + 2)
called :: -identity(1)
chained :: --1
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	loose := module.exprs[module.globals[0].expr]
	grouped := module.exprs[module.globals[1].expr]
	called := module.exprs[module.globals[2].expr]
	chained := module.exprs[module.globals[3].expr]
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, loose.kind, ast.Expr_Kind.Add)
	testing.expect_value(t, module.exprs[loose.left].kind, ast.Expr_Kind.Negate)
	testing.expect_value(t, grouped.kind, ast.Expr_Kind.Negate)
	testing.expect_value(t, module.exprs[grouped.left].kind, ast.Expr_Kind.Add)
	testing.expect_value(t, called.kind, ast.Expr_Kind.Negate)
	testing.expect_value(t, module.exprs[called.left].kind, ast.Expr_Kind.Call)
	testing.expect_value(t, chained.kind, ast.Expr_Kind.Negate)
	testing.expect_value(t, module.exprs[chained.left].kind, ast.Expr_Kind.Negate)
}

@(test)
parser_accepts_comptime_prefix_and_block_expressions :: proc(t: ^testing.T) {
	text := `sum func(a, b int) int { return a + b }
literal :: $32
call :: $sum(1, 2) + 3
block :: ${
	yield 4
}
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	literal := module.exprs[module.globals[0].expr]
	call_add := module.exprs[module.globals[1].expr]
	call := module.exprs[call_add.left]
	block := module.exprs[module.globals[2].expr]

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, literal.kind, ast.Expr_Kind.Comptime)
	testing.expect_value(t, module.exprs[literal.left].kind, ast.Expr_Kind.Integer)
	testing.expect_value(t, call_add.kind, ast.Expr_Kind.Add)
	testing.expect_value(t, call.kind, ast.Expr_Kind.Comptime)
	testing.expect_value(t, module.exprs[call.left].kind, ast.Expr_Kind.Call)
	testing.expect_value(t, block.kind, ast.Expr_Kind.Comptime)
	testing.expect_value(t, len(block.body), 1)
	testing.expect_value(t, module.statements[block.body[0]].kind, ast.Stmt_Kind.Yield)
}

nested_expression_source :: proc(call: bool, depth: int) -> string {
	builder := strings.builder_make()
	defer strings.builder_destroy(&builder)
	if call {
		strings.write_string(&builder, "identity func(value i32) i32 { return value }\nvalue :: ")
		for _ in 0..<depth {
			strings.write_string(&builder, "identity(")
		}
	} else {
		strings.write_string(&builder, "value :: ")
		for _ in 0..<depth {
			strings.write_byte(&builder, '(')
		}
	}
	strings.write_byte(&builder, '1')
	for _ in 0..<depth {
		strings.write_byte(&builder, ')')
	}
	strings.write_string(&builder, "\nmain func() void {}\n")
	return strings.clone(strings.to_string(builder))
}

nested_negation_source :: proc(depth: int) -> string {
	builder := strings.builder_make()
	defer strings.builder_destroy(&builder)
	strings.write_string(&builder, "value :: ")
	for _ in 0..<depth {
		strings.write_byte(&builder, '-')
	}
	strings.write_string(&builder, "1\nmain func() void {}\n")
	return strings.clone(strings.to_string(builder))
}

parse_nesting_result :: proc(text: string) -> (count: int, found_budget: bool) {
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)
	for diagnostic in diagnostics.items {
		found_budget = found_budget || strings.contains(diagnostic.message, "expression nesting exceeds 256 levels")
	}
	return len(diagnostics.items), found_budget
}

@(test)
parser_enforces_explicit_expression_nesting_budget :: proc(t: ^testing.T) {
	modes := [?]bool{false, true}
	for call in modes {
		at_limit := nested_expression_source(call, parser.MAX_EXPRESSION_NESTING)
		defer delete(at_limit)
		count, found := parse_nesting_result(at_limit)
		testing.expect_value(t, count, 0)
		testing.expect(t, !found)

		over_limit := nested_expression_source(call, parser.MAX_EXPRESSION_NESTING+1)
		defer delete(over_limit)
		_, found = parse_nesting_result(over_limit)
		testing.expect(t, found)
	}

	at_limit := nested_negation_source(parser.MAX_EXPRESSION_NESTING)
	defer delete(at_limit)
	count, found := parse_nesting_result(at_limit)
	testing.expect_value(t, count, 0)
	testing.expect(t, !found)

	over_limit := nested_negation_source(parser.MAX_EXPRESSION_NESTING+1)
	defer delete(over_limit)
	_, found = parse_nesting_result(over_limit)
	testing.expect(t, found)
}

@(test)
cli_parses_ordered_link_options_and_rejects_invalid_forms :: proc(t: ^testing.T) {
	options, valid := parse_cli_args([]string{
		"brolang",
		"app",
		"--c-link",
		"native.c",
		"-o",
		"app.out",
		"--c-library-path",
		"vendor/lib",
		"--c-library",
		"thing",
		"--c-link",
		"helper.o",
		"--c-include-path",
		"vendor/include",
		"--c-define",
		"FEATURE=1",
		"--root",
		".",
		"--target",
		"aarch64-macos",
	})
	defer delete(options.link_arguments)
	defer delete(options.c_options.include_paths)
	defer delete(options.c_options.defines)

	testing.expect(t, valid)
	testing.expect_value(t, options.input_path, "app")
	testing.expect_value(t, options.output_path, "app.out")
	testing.expect_value(t, options.project_root, ".")
	testing.expect_value(t, len(options.link_arguments), 4)
	testing.expect_value(t, options.link_arguments[0].kind, linker.Kind.Input)
	testing.expect_value(t, options.link_arguments[0].value, "native.c")
	testing.expect_value(t, options.link_arguments[1].kind, linker.Kind.Library_Path)
	testing.expect_value(t, options.link_arguments[2].kind, linker.Kind.Library)
	testing.expect_value(t, options.link_arguments[3].value, "helper.o")
	testing.expect_value(t, options.c_options.include_paths[0], "vendor/include")
	testing.expect_value(t, options.c_options.defines[0], "FEATURE=1")
	testing.expect_value(t, target.name(options.target), "aarch64-macos")

	_, unknown_valid := parse_cli_args([]string{"brolang", "app", "-o", "out", "--unknown", "value"})
	_, incomplete_valid := parse_cli_args([]string{"brolang", "app", "-o"})
	_, duplicate_output_valid := parse_cli_args([]string{"brolang", "app", "-o", "one", "-o", "two"})
	_, duplicate_root_valid := parse_cli_args([]string{"brolang", "app", "-o", "out", "--root", ".", "--root", "other"})
	_, duplicate_empty_output_valid := parse_cli_args([]string{"brolang", "app", "-o", "", "-o", "two"})
	_, invalid_target := parse_cli_args([]string{"brolang", "app", "-o", "out", "--target", "x86_64-linux"})
	_, legacy_link := parse_cli_args([]string{"brolang", "app", "-o", "out", "--link", "native.c"})
	_, legacy_library_path := parse_cli_args([]string{"brolang", "app", "-o", "out", "--library-path", "vendor/lib"})
	_, legacy_library := parse_cli_args([]string{"brolang", "app", "-o", "out", "--library", "thing"})
	testing.expect(t, !unknown_valid)
	testing.expect(t, !incomplete_valid)
	testing.expect(t, !duplicate_output_valid)
	testing.expect(t, !duplicate_root_valid)
	testing.expect(t, !duplicate_empty_output_valid)
	testing.expect(t, !invalid_target)
	testing.expect(t, !legacy_link)
	testing.expect(t, !legacy_library_path)
	testing.expect(t, !legacy_library)
}

@(test)
translate_c_helpers_resolve_zig_libc_headers :: proc(t: ^testing.T) {
	lib_dir, parsed := zig_lib_dir_from_env_output(".{\n    .lib_dir = \"/zig/lib\",\n}\n")
	defer delete(lib_dir)

	header, resolved := resolve_translate_c_header("native.h", []string{"examples/interop/header/include"})
	defer delete(header)

	testing.expect(t, is_translate_c_command("--translate-c"))
	testing.expect(t, is_translate_c_command("translate-c"))
	testing.expect(t, parsed)
	testing.expect_value(t, lib_dir, "/zig/lib")
	testing.expect(t, resolved)
	testing.expect(t, strings.has_suffix(header, "examples/interop/header/include/native.h"))
}

@(test)
parser_accepts_bare_and_aliased_imports :: proc(t: ^testing.T) {
	text := `import
	"../math"
other :: import "../math"
escaped :: import "dir\"name\\tail"
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(module.imports), 3)
	testing.expect_value(t, symbol.resolve(&symbols, module.imports[0].alias), "")
	testing.expect_value(t, module.imports[0].path, "../math")
	testing.expect_value(t, symbol.resolve(&symbols, module.imports[1].alias), "other")
	testing.expect_value(t, module.imports[2].path, "dir\"name\\tail")
}

@(test)
parser_accepts_chained_field_access :: proc(t: ^testing.T) {
	text := `main func() void {
	_ = first.second.value
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
lexer_diagnoses_invalid_import_strings :: proc(t: ^testing.T) {
	text := "import \"bad\\q\"\nimport \"unterminated\n"
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)

	testing.expect_value(t, len(diagnostics.items), 2)
}

@(test)
package_loader_discovers_lexical_immediate_source_files :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	module, loaded := loader.load("examples/packages/basic/app", &sources, &diagnostics, &symbols)
	defer ast.destroy_module(&module)

	testing.expect(t, loaded)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(module.packages), 2)
	testing.expect_value(t, len(module.files), 3)
	testing.expect(t, strings.has_suffix(sources.items[module.files[0].source].path, "/main.bro"))
	testing.expect(t, strings.has_suffix(sources.items[module.files[1].source].path, "/value.hon"))
	testing.expect(t, strings.has_suffix(sources.items[module.files[2].source].path, "/math.bro"))
}

@(test)
multi_source_diagnostics_report_the_originating_file :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	module, loaded := loader.load("examples/packages/file_local/app", &sources, &diagnostics, &symbols)
	defer ast.destroy_module(&module)
	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect(t, loaded)
	found := false
	for _, diagnostic_index in diagnostics.items {
		message := source.format(&diagnostics, source.diagnostic_id(diagnostic_index))
		if strings.contains(message, "--> ") && strings.contains(message, "/b.bro:2:9") &&
		   strings.contains(message, "unknown symbol 'math'") {
			found = true
		}
		delete(message)
	}
	testing.expect(t, found)
}

@(test)
semantic_lookup_diagnoses_wrong_declaration_kinds :: proc(t: ^testing.T) {
	text := `value :: 1
give func() i8 {
	return 1
}
main func() void {
	_ = value()
	_ = give
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_global := false
	found_old_function_error := false
	for diagnostic in diagnostics.items {
		found_global = found_global || strings.contains(diagnostic.message, "'value' is a global, not a function")
		found_old_function_error =
			found_old_function_error ||
			strings.contains(diagnostic.message, "'give' is a function, not a global value")
	}
	testing.expect(t, found_global)
	testing.expect(t, !found_old_function_error)
}

@(test)
pipeline_emits_specialized_calling_conventions_and_checked_add :: proc(t: ^testing.T) {
	text := `sum_c c_func(a, b int) int {
	return a + b
}
sum_bro func(a, b int) int {
	return a + b
}
main func() void {
	_ = sum_c(1, 2)
	_ = sum_bro(1, 2)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)
	second_llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(second_llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, llvm_text, second_llvm_text)
	testing.expect(t, strings.contains(llvm_text, "define signext i8 @bro_c__p0__sum_c__i8__i8"))
	testing.expect(t, strings.contains(llvm_text, "define internal fastcc i8 @bro__p0__sum_bro__i8__i8"))
	testing.expect(t, strings.contains(llvm_text, "@llvm.sadd.with.overflow.i8"))
}

@(test)
pipeline_emits_only_referenced_foreign_declarations_with_exact_names :: proc(t: ^testing.T) {
	text := `used c_func(a, b i32) i32
unused c_func() i32
bodyful c_func(value i32) i32 {
	return value
}
main func() void {
	_ = used(1, 2)
	_ = bodyful(3)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "declare i32 @used(i32, i32)"))
	testing.expect(t, strings.contains(llvm_text, "call i32 @used(i32 1, i32 2)"))
	testing.expect(t, !strings.contains(llvm_text, "@unused("))
	testing.expect(t, strings.contains(llvm_text, "define i32 @bro_c__p0__bodyful__i32"))
}

@(test)
c_primitives_remain_distinct_with_apple_silicon_representations :: proc(t: ^testing.T) {
	testing.expect(t, types.C_CHAR != types.C_SCHAR)
	testing.expect(t, types.C_SCHAR != types.C_UCHAR)
	testing.expect(t, types.C_INT != types.I32)
	testing.expect(t, types.C_ULONG != types.U64)
	testing.expect_value(t, types.representation(types.C_CHAR), types.I8)
	testing.expect_value(t, types.representation(types.C_SCHAR), types.I8)
	testing.expect_value(t, types.representation(types.C_UCHAR), types.U8)
	testing.expect_value(t, types.representation(types.C_SHORT), types.I16)
	testing.expect_value(t, types.representation(types.C_USHORT), types.U16)
	testing.expect_value(t, types.representation(types.C_INT), types.I32)
	testing.expect_value(t, types.representation(types.C_UINT), types.U32)
	testing.expect_value(t, types.representation(types.C_LONG), types.I64)
	testing.expect_value(t, types.representation(types.C_ULONG), types.U64)
	testing.expect_value(t, types.representation(types.C_LONGLONG), types.I64)
	testing.expect_value(t, types.representation(types.C_ULONGLONG), types.U64)
	testing.expect_value(t, types.representation(types.C_FLOAT), types.F32)
	testing.expect_value(t, types.representation(types.C_DOUBLE), types.F64)
	testing.expect_value(t, types.representation(types.C_LONGDOUBLE), types.F64)
	testing.expect_value(t, types.c_vararg_promotion(types.I8), types.C_INT)
	testing.expect_value(t, types.c_vararg_promotion(types.U16), types.C_INT)
	testing.expect_value(t, types.c_vararg_promotion(types.C_CHAR), types.C_INT)
	testing.expect_value(t, types.c_vararg_promotion(types.C_USHORT), types.C_INT)
	testing.expect_value(t, types.c_vararg_promotion(types.F32), types.C_DOUBLE)
	testing.expect_value(t, types.c_vararg_promotion(types.C_FLOAT), types.C_DOUBLE)
	testing.expect_value(t, types.c_vararg_promotion(types.U32), types.U32)
	testing.expect_value(t, types.c_vararg_promotion(types.C_DOUBLE), types.C_DOUBLE)
	testing.expect_value(t, target.llvm_triple(target.DEFAULT), "arm64-apple-macosx13.0.0")
}

@(test)
interop_foundation_emits_compounds_and_narrow_c_abi_attributes :: proc(t: ^testing.T) {
	text := `Point :: struct {
	x i32
	y i32
}
signed c_func(value c_char) c_char
unsigned c_func(value c_uchar) c_uchar
exact c_func(value u32) u32
fallback func() i32 {
	return 9
}
main func() void {
	c :: 1
	values [2;0]mut u8 = [1, 2]
	point Point :: Point{x = 3, y = 4}
	maybe ?i32 = 5
	_ = c
	_ = values[2]
	_ = (&values).ptr + 1
	_ = values.len
	_ = values[0..2]
	_ = "hello".ptr
	_ = "hello".len
	_ = point.x
	_ = maybe?
	_ = maybe orelse 0
	_ = maybe orelse fallback()
	_ = signed(1)
	_ = unsigned(1)
	_ = exact(1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "target triple = \"arm64-apple-macosx13.0.0\""))
	testing.expect(t, strings.contains(llvm_text, "declare signext i8 @signed(i8 signext)"))
	testing.expect(t, strings.contains(llvm_text, "declare zeroext i8 @unsigned(i8 zeroext)"))
	testing.expect(t, strings.contains(llvm_text, "declare i32 @exact(i32)"))
	testing.expect(t, strings.contains(llvm_text, "@bro.str.0 = private unnamed_addr constant [6 x i8] c\"hello\\00\""))
	testing.expect(t, strings.contains(llvm_text, "getelementptr [3 x i8]"))
	testing.expect(t, strings.contains(llvm_text, "attempted to unwrap none"))
	testing.expect(t, strings.contains(llvm_text, "orelse_fallback"))
	testing.expect(t, strings.contains(llvm_text, "orelse_some"))
}

@(test)
string_literals_preserve_static_length_and_sentinel_through_pointer_views :: proc(t: ^testing.T) {
	text := `take_sentinel_pointer func(_ [*;0]u8) void {}
take_mut_sentinel_pointer func(_ [*;0]mut u8) void {}
take_pointer func(_ *u8) void {}
take_sentinel_slice func(_ [;0]u8) void {}
take_mut_sentinel_slice func(_ [;0]mut u8) void {}
take_slice func(_ []u8) void {}
take_c_string c_func(value *c_char) c_int
take_c_sentinel c_func(value [*;0]c_char) c_int
main func() void {
	text :: "hello"
	values [2;0]mut u8 = [1, 2]
	pointer :: &values
	_ = text.len
	_ = text.ptr
	_ = text[0]
	_ = text[1..]
	_ = pointer.len
	_ = pointer.ptr
	_ = pointer[0]
	_ = pointer[1..]
	offset [*;0]u8 :: text.ptr + 1
	suffix [*;0]u8 :: text[1..].ptr
	middle []u8 :: text[1..3]
	_ = offset
	_ = suffix
	_ = middle
	take_sentinel_pointer(text)
	take_pointer(text)
	take_sentinel_slice(text)
	take_slice(text)
	take_mut_sentinel_pointer(pointer)
	take_mut_sentinel_slice(pointer)
	take_sentinel_pointer(pointer)
	take_sentinel_slice(pointer)
	_ = take_c_string(text)
	_ = take_c_sentinel(text)
	_ = take_c_string(text.ptr)
	_ = take_c_sentinel(text.ptr)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	string_type := types.INVALID
	decays := 0
	for expr in hir_module.exprs {
		if expr.kind == .String {
			string_type = expr.type
		}
		if expr.kind == .Decay_Array_Pointer {
			decays += 1
		}
	}
	pointer, array, string_ok := types.array_pointer(string_type, &hir_module.types)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, string_ok && !pointer.mutable && array.child == types.U8 &&
	                  array.count == 5 && array.has_sentinel && array.sentinel == 0)
	testing.expect(t, decays >= 6)
	testing.expect(t, strings.contains(llvm_text, "@bro.str.0 = private unnamed_addr constant [6 x i8] c\"hello\\00\""))
	testing.expect(t, strings.contains(llvm_text, "declare i32 @take_c_string(ptr)"))
	testing.expect(t, strings.contains(llvm_text, "declare i32 @take_c_sentinel(ptr)"))
}

@(test)
multiline_strings_join_lines_and_strip_indentation :: proc(t: ^testing.T) {
	// Source written double-quoted (not a raw `...` literal) because the
	// backtick is the multi-line string marker. Covers basic join, the
	// trailing-newline form, a blank line in the middle, and value-on-next-line.
	text := "main func() void {\n" +
		"\tbasic ::\n\t\t`a\n\t\t`b\n" +
		"\ttrailing ::\n\t\t`hello\n\t\t`world\n\t\t`\n" +
		"\tgapped ::\n\t\t`x\n\t\t`\n\t\t`y\n" +
		"\t_ = basic\n\t_ = trailing\n\t_ = gapped\n}\n"
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(ast_module.strings), 3)
	testing.expect_value(t, ast_module.strings[0], "a\nb")
	testing.expect_value(t, ast_module.strings[1], "hello\nworld\n")
	testing.expect_value(t, ast_module.strings[2], "x\n\ny")

	// A multi-line string is an ordinary string literal: @[N;0]u8.
	string_type := types.INVALID
	for expr in hir_module.exprs {
		if expr.kind == .String {
			string_type = expr.type
			break
		}
	}
	pointer, array, string_ok := types.array_pointer(string_type, &hir_module.types)
	testing.expect(t, string_ok && !pointer.mutable && array.child == types.U8 &&
		array.has_sentinel && array.sentinel == 0)
}

@(test)
array_pointer_and_c_string_coercion_restrictions_are_diagnosed :: proc(t: ^testing.T) {
	text := `take_c_string c_func(value *c_char) c_int
take_mut_c_string c_func(value *mut c_char) c_int
take_pointer func(value *u8) void {}
take_mut_pointer func(value *mut u8) void {}
take_slice func(value []u8) void {}
bad_sentinel func(value [*;256]u8) void {}
main func() void {
	values [1;0]mut u8 = [1]
	_ = values.ptr
	take_pointer(values)
	take_slice(values)
	ordinary *u8 :: "hello"
	nonzero [1;'\n']mut u8 = [1]
	take_pointer("hello"[1..])
	_ = take_c_string(ordinary)
	_ = take_c_string((&nonzero).ptr)
	_ = take_c_string(1)
	take_mut_pointer("hello")
	_ = take_mut_c_string("hello")
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	conversion_errors := 0
	array_ptr_error := false
	sentinel_error := false
	for diagnostic in diagnostics.items {
		conversion_errors += 1 if strings.contains(diagnostic.message, "cannot implicitly convert") else 0
		array_ptr_error = array_ptr_error ||
		                  strings.contains(diagnostic.message, "arrays do not expose '.ptr'")
		sentinel_error = sentinel_error ||
		                 strings.contains(diagnostic.message, "sentinel value does not fit array, slice, or pointer")
	}
	testing.expect_value(t, conversion_errors, 8)
	testing.expect(t, array_ptr_error)
	testing.expect(t, sentinel_error)
}

@(test)
immutable_pointer_and_slice_bindings_preserve_mutable_pointees :: proc(t: ^testing.T) {
	text := `main func() void {
	values [2]mut u8 = [1, 2]
	pointer *mut u8 :: (&values).ptr
	slice []mut u8 :: values[0..]
	pointer[0] = 3
	slice[1] = 4
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
many_item_pointer_slices_compile_and_run :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-pointer-slices"
	main_path := "/tmp/brolang-test-pointer-slices/main.bro"
	output := "/tmp/brolang-test-pointer-slices-output"
	text := `main func() i32 {
	values [4]mut i32 = [3, 4, 5, 6]
	pointer *mut i32 :: (&values).ptr
	const_pointer *i32 :: pointer
	all []mut i32 :: pointer[..4]
	middle []mut i32 :: pointer[1..3]
	readonly []i32 :: const_pointer[..2]

	if (all.len != 4) return 1
	if (middle.len != 2) return 2
	all[0] = 10
	if (readonly[0] != 10) return 3
	if (middle.ptr[0] != 4) return 4
	return 0
}
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	status := compiler_core.compile_package(directory, output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
many_item_pointer_slices_require_end_bound :: proc(t: ^testing.T) {
	text := `main func() void {
	values [2]i32 = [1, 2]
	pointer *i32 :: (&values).ptr
	_ = pointer[..]
	_ = pointer[1..]
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	end_bound_errors := 0
	for diagnostic in diagnostics.items {
		if strings.contains(diagnostic.message, "many-item pointer slicing requires an explicit end bound") {
			end_bound_errors += 1
		}
	}
	testing.expect_value(t, end_bound_errors, 2)
}

@(test)
layout_builtins_compile_and_run :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-layout-builtins"
	main_path := "/tmp/brolang-test-layout-builtins/main.bro"
	output := "/tmp/brolang-test-layout-builtins-output"
	text := `Point :: struct {
	x i32
	y u8
}

Opaque :: opaque
Color :: enum {
	red
	blue
}
UserID :: distinct u32
SIZE_GLOBAL :: sizeof!(i32)

needs_usize func(value usize) usize {
	return value
}

buffer func($T type) [sizeof!(T)]u8 {
	data [sizeof!(T)]u8 = undefined
	return data
}

main func() i32 {
	bytes [_]u8 :: buffer(i32)
	if (needs_usize(SIZE_GLOBAL) != 4) return 1
	if (bytes.len != 4) return 2
	if (sizeof!([3]u8) != 3) return 3
	if (sizeof!([]u8) != 16) return 4
	if (alignof!([]u8) != 8) return 5
	if (sizeof!(*anyopaque) != 8) return 6
	if (sizeof!(?*i32) != 8) return 7
	if (sizeof!(*Opaque) != 8) return 8
	if (sizeof!(Color) != 2) return 9
	if (alignof!(Color) != 2) return 10
	if (sizeof!(Point) != 8) return 11
	if (alignof!(Point) != 4) return 12
	if (sizeof!(UserID) != 4) return 13
	if (alignof!(UserID) != 4) return 14
	return 0
}
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	status := compiler_core.compile_package(directory, output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
integer_bound_builtins_compile_and_run :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-integer-bounds"
	main_path := "/tmp/brolang-test-integer-bounds/main.bro"
	output := "/tmp/brolang-test-integer-bounds-output"
	text := `MAX_U64 u64 :: maxval!(u64)

maximum func($T type) T {
	return maxval!(T)
}

main func() i32 {
	if (minval!(i8) != -128) return 1
	if (maxval!(i8) != 127) return 2
	if (minval!(u8) != 0) return 3
	if (maxval!(u8) != 255) return 4
	if (minval!(isize) != -9223372036854775808) return 5
	if (maxval!(usize) != 18446744073709551615) return 6
	if (MAX_U64 != 18446744073709551615) return 7
	if (maximum(u16) != 65535) return 8
	if (minval!(c_int) != -2147483648) return 9
	if (maxval!(c_ulong) != 18446744073709551615) return 10
	return 0
}
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	status := compiler_core.compile_package(directory, output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
integer_bound_builtins_reject_invalid_targets :: proc(t: ^testing.T) {
	text := `Named :: distinct u8
Choice :: enum { one }

main func() void {
	_ = minval!()
	_ = maxval!(u8, u16)
	_ = minval!(1)
	_ = maxval!(int)
	_ = maxval!(f32)
	_ = maxval!(bool)
	_ = maxval!(Named)
	_ = maxval!(Choice)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	bad_arity := 0
	bad_type := false
	bad_target := 0
	for diagnostic in diagnostics.items {
		bad_arity += 1 if strings.contains(diagnostic.message, "expects 1 argument") else 0
		bad_type = bad_type || strings.contains(diagnostic.message, "integer bound target must be a type")
		bad_target += 1 if strings.contains(diagnostic.message, "integer bound target must be a concrete integer type") else 0
	}
	testing.expect_value(t, bad_arity, 2)
	testing.expect(t, bad_type)
	testing.expect_value(t, bad_target, 5)
}

@(test)
layout_builtins_reject_unsized_targets :: proc(t: ^testing.T) {
	text := `Opaque :: opaque
Fn :: alias func() void

main func() void {
	_ = sizeof!(void)
	_ = alignof!(anyopaque)
	_ = sizeof!(Fn)
	_ = sizeof!(Opaque)
	_ = alignof!(1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	bad_layout_targets := 0
	target_type_error := false
	for diagnostic in diagnostics.items {
		bad_layout_targets += 1 if strings.contains(diagnostic.message, "layout target must be a sized runtime value type") else 0
		target_type_error = target_type_error || strings.contains(diagnostic.message, "layout target must be a type")
	}
	testing.expect_value(t, bad_layout_targets, 4)
	testing.expect(t, target_type_error)
}

@(test)
slicing_an_array_variable_takes_its_address_implicitly :: proc(t: ^testing.T) {
	// Milestone 10: `arr[a..b]` on an array variable slices without an explicit
	// `&`. The slice operand must be a pointer to the array (getelementptr off a
	// `ptr`), not the array value.
	text := `sink func(s []i32) i32 {
	return s[0]
}
main func() i32 {
	arr [4]i32 = [10, 20, 30, 40]
	full :: sink(arr[..])
	part :: sink(arr[1..3])
	return full + part
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "getelementptr [4 x i32], ptr"))
}

@(test)
slicing_an_array_rvalue_materializes_a_temporary :: proc(t: ^testing.T) {
	// The checker accepts slicing a non-location array (here, a by-value array
	// return). Lowering must store it into a temporary and slice that address;
	// otherwise the slice operand is an array value, which is an invalid pointer.
	text := `make_arr func() [4]i32 {
	return [1, 2, 3, 4]
}
sink func(s []i32) i32 {
	return s[0]
}
main func() i32 {
	return sink(make_arr()[0..])
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	// The materialization store of the array rvalue into its temporary.
	testing.expect(t, strings.contains(llvm_text, "store [4 x i32]"))
	testing.expect(t, strings.contains(llvm_text, "getelementptr [4 x i32], ptr"))
}

@(test)
field_and_index_access_on_an_rvalue_aggregate_materializes_it :: proc(t: ^testing.T) {
	// A by-value struct return is a temporary with no address. Reading a field,
	// slicing an array field, and taking its address must spill it into a
	// temporary and address that, rather than addressing the aggregate value.
	text := `Box :: struct {
	score i32
	data [4]i32
}
make_box func() Box {
	return Box { score = 7, data = [1, 2, 3, 4] }
}
sink func(s []i32) i32 {
	return s[0]
}
main func() i32 {
	s :: make_box().score
	v :: sink(make_box().data[0..])
	p :: &make_box().data
	return s + v + p^[1]
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	// The rvalue Box is spilled into a stack temporary (structs render as
	// %bro.type.N), then stored, then its fields are addressed off a `ptr`.
	// A regression addresses the aggregate value directly, which llc rejects.
	testing.expect(t, strings.contains(llvm_text, "alloca %bro.type."))
	testing.expect(t, strings.contains(llvm_text, "store %bro.type."))
	testing.expect(t, strings.contains(llvm_text, "getelementptr [4 x i32], ptr"))
}

@(test)
c_variadic_calls_promote_extras_and_emit_variadic_llvm :: proc(t: ^testing.T) {
text := `variadic c_func(tag c_int, ...) c_int
zero c_func(...) void
main func() void {
	narrow i8 :: -2
	unsigned u16 :: 3
	float_value f32 :: 4.0
	c_float_value c_float :: 5.0
	pointer *u8 :: "ok".ptr
	nullable ?*u8 :: pointer
	zero(pointer)
	_ = variadic(7, narrow, unsigned, float_value, c_float_value, pointer, nullable)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	promotions := 0
	for expr in hir_module.exprs {
		if expr.kind == .C_Vararg_Promote {
			promotions += 1
		}
	}
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, promotions, 4)
	found_hir_variadic := false
	for function in hir_module.functions {
		found_hir_variadic = found_hir_variadic || function.variadic
	}
	found_ir_variadic := false
	for function in ir_module.functions {
		found_ir_variadic = found_ir_variadic || function.variadic
	}
	testing.expect(t, found_hir_variadic)
	testing.expect(t, found_ir_variadic)
	testing.expect(t, strings.contains(llvm_text, "declare i32 @variadic(i32, ...)"))
	testing.expect(t, strings.contains(llvm_text, "declare void @zero(...)"))
	testing.expect(t, strings.contains(llvm_text, "sext i8"))
	testing.expect(t, strings.contains(llvm_text, "zext i16"))
	testing.expect(t, strings.contains(llvm_text, "fpext float"))
	testing.expect(t, strings.contains(llvm_text, "call void (...) @zero(ptr"))
	testing.expect(t, strings.contains(llvm_text, "call i32 (i32, ...) @variadic(i32 7, i32"))
	testing.expect(t, strings.contains(llvm_text, "double"))
	testing.expect(t, strings.contains(llvm_text, "ptr"))
}

@(test)
c_variadic_restrictions_and_extra_argument_types_are_diagnosed :: proc(t: ^testing.T) {
	text := `Record :: c_struct {
	value c_int
}
foreign c_func(...) void
requires c_func(value c_int, ...) void
native func(...) void
bodyful c_func(...) void {}
main func() void {
	values [1]u8 :: [1]
	record Record :: Record { value = 1 }
	foreign(values)
	foreign(record)
	requires()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	restricted := 0
	found_extra := false
	found_arity := false
	for diagnostic in diagnostics.items {
		if strings.contains(diagnostic.message, "must be a bodyless 'c_func' declaration") {
			restricted += 1
		}
		found_extra = found_extra || strings.contains(diagnostic.message, "C variadic argument must be a concrete scalar or pointer")
		found_arity = found_arity || strings.contains(diagnostic.message, "expects at least 1 arguments")
	}
	testing.expect_value(t, restricted, 2)
	testing.expect(t, found_extra)
	testing.expect(t, found_arity)
}

@(test)
variadicness_is_part_of_c_function_signature_compatibility :: proc(t: ^testing.T) {
	fixed := ast.Function{result=types.C_INT}
	variadic := ast.Function{result=types.C_INT, variadic=true}
	testing.expect(t, !checker.function_signatures_equal(fixed, variadic))
	testing.expect(t, !loader.function_signatures_equal(fixed, nil, types.C_INT, true))
}

@(test)
c_structs_are_by_value_and_bodyless_c_struct_uses_opaque :: proc(t: ^testing.T) {
	text := `Defined :: c_struct {
	value c_int
}
Opaque :: opaque
Bodyless :: c_struct
Empty :: c_struct {}
Bad :: c_struct {
	values []i32
}
read c_func(value @Defined) c_int
pass c_func(value Defined) Defined
bad_opaque c_func(value Opaque) void
main func() void {
	_ = pass(Defined { value = 1 })
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_opaque := false
	found_bodyless := false
	found_bad_layout := false
	found_empty := false
	for diagnostic in diagnostics.items {
		found_opaque = found_opaque || strings.contains(diagnostic.message, "cannot be passed by value")
		found_bodyless = found_bodyless || strings.contains(diagnostic.message, "use 'opaque'")
		found_bad_layout = found_bad_layout || strings.contains(diagnostic.message, "C-layout-compatible")
		found_empty = found_empty || strings.contains(diagnostic.message, "at least one field")
	}
	testing.expect(t, found_opaque)
	testing.expect(t, found_bodyless)
	testing.expect(t, found_bad_layout)
	testing.expect(t, found_empty)
}

@(test)
opaque_anyopaque_and_ptrcast_compile_and_lower :: proc(t: ^testing.T) {
	text := `Handle :: opaque
take func(_ ?*mut anyopaque) void {}
use_handle func(_ ?@mut Handle) void {}
main func() void {
	values [2]mut u8 = [1, 2]
	raw ?*mut anyopaque = (&values).ptr
	bytes ?*mut u8 = ptrcast!(u8, raw)
	take(bytes)
	if bytes |p| {
		p[1] = 5
	}

	one u8 = 1
	single ?@mut anyopaque = &one
	typed ?@mut u8 = ptrcast!(u8, single)
	if typed |p| {
		p^ = 2
	}

	handle ?@mut Handle = none
	use_handle(handle)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)

	hir_casts := 0
	for expr in hir_module.exprs {
		hir_casts += 1 if expr.kind == .Pointer_Cast else 0
	}
	ir_casts := 0
	for function in ir_module.functions {
		for instruction in function.instructions {
			ir_casts += 1 if instruction.op == .Pointer_Cast else 0
		}
	}

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, hir_casts, 2)
	testing.expect_value(t, ir_casts, 2)
}

@(test)
anyopaque_by_value_and_invalid_ptrcasts_are_rejected :: proc(t: ^testing.T) {
	text := `Callback :: alias c_func() void
main func() void {
	raw ?*mut anyopaque = none
	value anyopaque = undefined
	_ = ptrcast!(void, raw)
	_ = ptrcast!(anyopaque, raw)
	_ = ptrcast!(Callback, raw)
	_ = ptrcast!(u8, 1)
	_ = ptrcast!(1, raw)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_by_value := false
	found_bad_target := false
	found_bad_operand := false
	found_target_type := false
	for diagnostic in diagnostics.items {
		found_by_value = found_by_value || strings.contains(diagnostic.message, "could not infer a concrete type")
		found_bad_target = found_bad_target || strings.contains(diagnostic.message, "ptrcast! target must be a sized runtime object type")
		found_bad_operand = found_bad_operand || strings.contains(diagnostic.message, "ptrcast! operand must be a pointer")
		found_target_type = found_target_type || strings.contains(diagnostic.message, "ptrcast! target must be a type")
	}
	testing.expect(t, found_by_value)
	testing.expect(t, found_bad_target)
	testing.expect(t, found_bad_operand)
	testing.expect(t, found_target_type)
}

@(test)
old_intrinsic_spellings_are_not_recognized :: proc(t: ^testing.T) {
	text := `main func() void {
	_ = ptr_cast(1, 1)
	_ = size_of(1)
	_ = align_of(1)
	_ = min_value(1)
	_ = max_value(1)
	_ = div_trunc(1, 1)
	_ = div_floor(1, 1)
	_ = div_exact(1, 1)
	_ = div_ceil(1, 1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	names := [?]string{
		"ptr_cast", "size_of", "align_of", "min_value", "max_value",
		"div_trunc", "div_floor", "div_exact", "div_ceil",
	}
	found := [len(names)]bool{}
	for diagnostic in diagnostics.items {
		if !strings.contains(diagnostic.message, "unknown symbol") {
			continue
		}
		for name, index in names {
			found[index] = found[index] || strings.contains(diagnostic.message, name)
		}
	}
	for value in found {
		testing.expect(t, value)
	}
}

@(test)
bare_intrinsic_names_are_available_to_user_functions :: proc(t: ^testing.T) {
	text := `ptrcast func() i32 { return 1 }
sizeof func() i32 { return 2 }
alignof func() i32 { return 3 }
minval func() i32 { return 4 }
maxval func() i32 { return 5 }
divtrunc func() i32 { return 6 }
divfloor func() i32 { return 7 }
divexact func() i32 { return 8 }
divceil func() i32 { return 9 }
rem func() i32 { return 10 }
mod func() i32 { return 11 }
main func() i32 {
	return ptrcast() + sizeof() + alignof() + minval() + maxval() +
		divtrunc() + divfloor() + divexact() + divceil() + rem() + mod() - 66
}
`
	directory := "/tmp/brolang-test-user-intrinsic-names"
	main_path := "/tmp/brolang-test-user-intrinsic-names/main.bro"
	output := "/tmp/brolang-test-user-intrinsic-names-output"
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	testing.expect_value(t, compiler_core.compile_package(directory, output), 0)
}

@(test)
intrinsic_call_diagnostics_are_precise :: proc(t: ^testing.T) {
	text := `main func() void {
	_ = mystery!()
	_ = math.ptrcast!()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_unknown := false
	found_qualified := false
	for diagnostic in diagnostics.items {
		found_unknown = found_unknown || diagnostic.message == "unknown intrinsic 'mystery!'"
		found_qualified = found_qualified || diagnostic.message == "intrinsic calls must be unqualified"
	}
	testing.expect(t, found_unknown)
	testing.expect(t, found_qualified)
}

@(test)
malformed_intrinsic_calls_have_targeted_parse_diagnostics :: proc(t: ^testing.T) {
	cases := [?]struct {
		text, message: string,
	}{
		{`main func() void { _ = sizeof! }`, "expected '(' after intrinsic name"},
		{`callback func() void {}
main func() void { (callback)!() }
`, "intrinsic calls require a direct name"},
	}
	for test_case in cases {
		source_file := source.Source{path="test.bro", text=test_case.text}
		diagnostics := source.init_diagnostics(&source_file)
		symbols := symbol.init_table()
		stream := lexer.lex(&source_file, &diagnostics, &symbols)
		module := parser.parse(&stream, &source_file, &diagnostics)

		found := false
		for diagnostic in diagnostics.items {
			found = found || diagnostic.message == test_case.message
		}
		testing.expect(t, found)

		ast.destroy_module(&module)
		delete(stream.items)
		symbol.destroy_table(&symbols)
		source.destroy_diagnostics(&diagnostics)
	}
}

@(test)
aarch64_c_record_abi_classifies_fixed_parameters_and_results :: proc(t: ^testing.T) {
	text := `Small :: c_struct {
	left c_int
	right c_int
}
Medium :: c_struct {
	first c_int
	second c_int
	third c_int
}
Hfa :: c_struct {
	x c_float
	y c_float
}
Large :: c_struct {
	first c_long
	second c_long
	third c_long
}
small c_func(value Small) Small
medium c_func(value Medium) Medium
hfa c_func(value Hfa) Hfa
large c_func(value Large) Large
main func() void {
	_ = small(Small { left = 1, right = 2 })
	_ = medium(Medium { first = 1, second = 2, third = 3 })
	_ = hfa(Hfa { x = 1.0, y = 2.0 })
	_ = large(Large { first = 1, second = 2, third = 3 })
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "declare i64 @small(i64)"))
	testing.expect(t, strings.contains(llvm_text, "declare [2 x i64] @medium([2 x i64])"))
	testing.expect(t, strings.contains(llvm_text, "@hfa([2 x float])"))
	testing.expect(t, strings.contains(llvm_text, "declare void @large(ptr sret("))
	testing.expect(t, strings.contains(llvm_text, "call void @llvm.memcpy.p0.p0.i64"))
}

@(test)
invalid_foreign_declarations_are_eagerly_diagnosed_and_calls_trap :: proc(t: ^testing.T) {
	text := `bad c_func(value int) int
native func() i32
main func() void {
	_ = bad(1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	found_parameter := false
	found_result := false
	found_native := false
	for diagnostic in diagnostics.items {
		found_parameter = found_parameter || strings.contains(diagnostic.message, "requires concrete parameter types")
		found_result = found_result || strings.contains(diagnostic.message, "requires a concrete or void result type")
		found_native = found_native || strings.contains(diagnostic.message, "must use 'c_func'")
	}
	testing.expect(t, found_parameter)
	testing.expect(t, found_result)
	testing.expect(t, found_native)
	testing.expect(t, !strings.contains(llvm_text, "@bad("))
	testing.expect(t, strings.contains(llvm_text, "call void @bro.trap"))
}

@(test)
duplicate_foreign_symbols_across_packages_are_poisoned :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	ast_module, loaded := loader.load("examples/packages/foreign_duplicate/app", &sources, &diagnostics, &symbols)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	duplicate_count := 0
	for diagnostic in diagnostics.items {
		if strings.contains(diagnostic.message, "duplicate foreign symbol 'same'") {
			duplicate_count += 1
		}
	}
	testing.expect(t, loaded)
	testing.expect_value(t, duplicate_count, 2)
	testing.expect(t, !strings.contains(llvm_text, "@same("))
	testing.expect(t, strings.contains(llvm_text, "call void @bro.trap"))
}

@(test)
bodyless_root_main_recovers_as_a_trap_definition :: proc(t: ^testing.T) {
	text := "main c_func() i32\n"
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "main must have a body")
	}
	testing.expect(t, found)
	testing.expect_value(t, len(ir_module.functions), 1)
	testing.expect_value(t, ir_module.functions[0].implementation, ir.Implementation.Definition)
	testing.expect(t, strings.contains(llvm_text, "define i32 @main()"))
	testing.expect(t, !strings.contains(llvm_text, "declare i32 @main()"))
}

@(test)
milestone_33_injects_explicit_io_provider_and_runs_std_io :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	ast_module, loaded := loader.load(
		"examples/programs/io",
		&sources,
		&diagnostics,
		&symbols,
		project_root_path=".",
	)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect(t, loaded)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, hir_module.injected_main != hir.INVALID_FUNCTION)
	testing.expect(t, hir_module.io_provider != hir.INVALID_FUNCTION)
	testing.expect_value(t, count_substring_occurrences(llvm_text, "define i32 @main()"), 1)
	testing.expect_value(t, count_substring_occurrences(llvm_text, "define internal fastcc i32 @bro__p0__main__"), 1)
	testing.expect_value(t, count_substring_occurrences(llvm_text, "declare i64 @write("), 1)

	output := "/tmp/brolang-test-io"
	defer _ = os.remove(output)
	status := compiler_core.compile_package(
		"examples/programs/io",
		output,
		nil,
		target.DEFAULT,
		cimport.Options{},
		".",
	)
	testing.expect_value(t, status, 0)
	state, stdout, stderr, _ := os2.process_exec(
		os2.Process_Desc{command=[]string{output}},
		context.allocator,
	)
	defer delete(stdout)
	defer delete(stderr)
	testing.expect_value(t, state.exit_code, 0)
	testing.expect_value(t, string(stdout),
		"io-ok 37 {bro}\n" +
		"bounds=-128/255 -32768/65535 -2147483648/4294967295 -9223372036854775808/18446744073709551615 " +
		"-9223372036854775808/18446744073709551615 -128/127 -128/255 -32768/65535 -2147483648/4294967295 " +
		"-9223372036854775808/18446744073709551615 -9223372036854775808/18446744073709551615 0/0 1/1 -1/1\n",
	)
}

@(test)
std_io_opens_existing_files_through_the_captured_provider :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-file-io"
	main_path := "/tmp/brolang-test-file-io/main.bro"
	data_path := "/tmp/brolang-test-file-io/data"
	output := "/tmp/brolang-test-file-io/app"
	seed := "xxxxx"
	text := `io :: import "@std/io"
process :: import "@std/process"

missing_fails func(system io.Io) bool {
	_ = io.open(system, "/tmp/brolang-test-file-io/missing", .read_only) catch |err| {
		return err == .open_failed
	}
	return false
}

wrong_read_fails func(file io.File) bool {
	buffer [1]mut u8 = [0]
	_ = io.read(io.reader(file), buffer[..]) catch |err| {
		return err == .not_open_for_reading
	}
	return false
}

wrong_write_fails func(file io.File) bool {
	_ = io.write(io.writer(file), "x") catch |err| {
		return err == .not_open_for_writing
	}
	return false
}

main func(init process.Init) i32 {
	if !missing_fails(init.io) {
		return 1
	}

	read_file io.File :: io.open(init.io, "/tmp/brolang-test-file-io/data", .read_only) catch |_| {
		return 2
	}
	buffer [5]mut u8 = [0, 0, 0, 0, 0]
	count usize = io.read(io.reader(read_file), buffer[..]) catch |_| {
		return 4
	}
	if count != 5 or buffer[0] != 'x' or !wrong_write_fails(read_file) {
		return 5
	}
	io.close(read_file) catch |_| {
		return 6
	}

	write_file io.File :: io.open(init.io, "/tmp/brolang-test-file-io/data", .write_only) catch |_| {
		return 7
	}
	if !wrong_read_fails(write_file) {
		return 8
	}
	io.write_all(io.writer(write_file), "bro") catch |_| {
		return 9
	}
	io.close(write_file) catch |_| {
		return 10
	}

	read_write_file io.File :: io.open(init.io, "/tmp/brolang-test-file-io/data", .read_write) catch |_| {
		return 11
	}
	count = io.read(io.reader(read_write_file), buffer[..]) catch |_| {
		return 12
	}
	if count != 5 or buffer[0] != 'b' or buffer[1] != 'r' or buffer[2] != 'o' {
		return 13
	}
	io.write_all(io.writer(read_write_file), "!") catch |_| {
		return 14
	}
	io.close(read_write_file) catch |_| {
		return 15
	}
	return 0
}
`

	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	testing.expect(t, os.write_entire_file(data_path, transmute([]byte)seed))

	status := compiler_core.compile_package(
		directory,
		output,
		nil,
		target.DEFAULT,
		cimport.Options{},
		".",
	)
	testing.expect_value(t, status, 0)
	state, stdout, stderr, _ := os2.process_exec(
		os2.Process_Desc{command=[]string{output}},
		context.allocator,
	)
	defer delete(stdout)
	defer delete(stderr)
	testing.expect_value(t, state.exit_code, 0)
	testing.expect_value(t, len(stdout), 0)
	testing.expect_value(t, len(stderr), 0)

	data, ok := os.read_entire_file(data_path)
	defer delete(data)
	testing.expect(t, ok)
	testing.expect_value(t, string(data), "broxx!")
}

@(test)
milestone_33_rejects_non_io_and_extra_main_parameters :: proc(t: ^testing.T) {
	cases := [?]string{
		"main func(value i32) void {}\n",
		"main func(left, right i32) void {}\n",
		"main func($value i32) void {}\n",
	}
	for text in cases {
		source_file := source.Source{path="test.bro", text=text}
		diagnostics := source.init_diagnostics(&source_file)
		symbols := symbol.init_table()
		stream := lexer.lex(&source_file, &diagnostics, &symbols)
		ast_module := parser.parse(&stream, &source_file, &diagnostics)
		hir_module := checker.check(&ast_module, &diagnostics, &symbols)

		found := false
		for diagnostic in diagnostics.items {
			found = found || strings.contains(
				diagnostic.message,
				"take no parameters or one @std/process Init",
			)
		}
		testing.expect(t, found)

		hir.destroy_module(&hir_module)
		ast.destroy_module(&ast_module)
		delete(stream.items)
		symbol.destroy_table(&symbols)
		source.destroy_diagnostics(&diagnostics)
	}
}

@(test)
milestone_37_rejects_direct_io_main_parameter :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-direct-io-main"
	main_path := "/tmp/brolang-test-direct-io-main/main.bro"
	text := `io :: import "@std/io"
main func(system io.Io) void {
	_ = system
}
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))

	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	ast_module, loaded := loader.load(directory, &sources, &diagnostics, &symbols, project_root_path=".")
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(
			diagnostic.message,
			"take no parameters or one @std/process Init",
		)
	}
	testing.expect(t, loaded)
	testing.expect(t, found)
}

@(test)
milestone_37_validates_process_init_and_hidden_system_provider :: proc(t: ^testing.T) {
	Case :: struct {
		io_source: string,
		process_source: string,
		message: string,
	}
	cases := []Case{
		{
			io_source=`Io :: struct { value i32 }
system func() Io { return Io {value = 0} }
`,
			process_source=`io :: import "@std/io"
Init :: struct { io io.Io }
`,
			message="does not provide the required 'hide system func() Io'",
		},
		{
			io_source=`Io :: struct { value i32 }
hide system func() Io { return Io {value = 0} }
`,
			process_source=`io :: import "@std/io"
Init :: struct { io io.Io, extra i32 }
`,
			message="Init must be an auto-layout record containing exactly 'io io.Io'",
		},
	}
	for test_case, index in cases {
		root := fmt.tprintf("/tmp/brolang-test-process-schema-%d", index)
		app := fmt.tprintf("%s/app", root)
		io_dir := fmt.tprintf("%s/std/io", root)
		process_dir := fmt.tprintf("%s/std/process", root)
		main_source: string = `process :: import "@std/process"
main func(init process.Init) void { _ = init }
`
		_ = os2.remove_all(root)
		defer _ = os2.remove_all(root)
		testing.expect(t, os2.make_directory_all(app) == nil)
		testing.expect(t, os2.make_directory_all(io_dir) == nil)
		testing.expect(t, os2.make_directory_all(process_dir) == nil)
		testing.expect(t, os.write_entire_file(
			fmt.tprintf("%s/main.bro", app), transmute([]byte)main_source,
		))
		testing.expect(t, os.write_entire_file(
			fmt.tprintf("%s/io.bro", io_dir), transmute([]byte)test_case.io_source,
		))
		testing.expect(t, os.write_entire_file(
			fmt.tprintf("%s/process.bro", process_dir), transmute([]byte)test_case.process_source,
		))

		sources := source.init_store()
		diagnostics := source.init_store_diagnostics(&sources)
		symbols := symbol.init_table()
		ast_module, loaded := loader.load(app, &sources, &diagnostics, &symbols, project_root_path=root)
		hir_module := checker.check(&ast_module, &diagnostics, &symbols)
		found := false
		for diagnostic in diagnostics.items {
			found = found || strings.contains(diagnostic.message, test_case.message)
		}
		testing.expect(t, loaded)
		testing.expect(t, found)
		hir.destroy_module(&hir_module)
		ast.destroy_module(&ast_module)
		symbol.destroy_table(&symbols)
		source.destroy_diagnostics(&diagnostics)
		source.destroy_store(&sources)
	}
}

@(test)
milestone_37_tuples_reflection_expand_for_and_debug_print_compile_and_run :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	ast_module, loaded := loader.load(
		"examples/programs/tuples", &sources, &diagnostics, &symbols, project_root_path=".",
	)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)
	testing.expect(t, loaded)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, !strings.contains(llvm_text, "FormatToken"))
	testing.expect(t, !strings.contains(llvm_text, "parse_format"))
	testing.expect(t, !strings.contains(llvm_text, "format_field_name"))
	testing.expect(t, !strings.contains(llvm_text, "FieldInfo"))
	testing.expect(t, !strings.contains(llvm_text, "RecordInfo"))

	output := "/tmp/brolang-test-tuples"
	defer _ = os.remove(output)
	status := compiler_core.compile_package(
		"examples/programs/tuples", output, nil, target.DEFAULT, cimport.Options{}, ".",
	)
	testing.expect_value(t, status, 0)
	state, stdout, stderr, _ := os2.process_exec(
		os2.Process_Desc{command=[]string{output}}, context.allocator,
	)
	defer delete(stdout)
	defer delete(stderr)
	testing.expect_value(t, state.exit_code, 0)
	testing.expect_value(t, string(stdout), "")
	testing.expect_value(t, string(stderr), "hello!\ntuple=40/bro, limits=-9223372036854775808/18446744073709551615")
}

@(test)
expanded_matches_and_tag_intrinsics_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-expand"
	defer _ = os.remove(output)
	status := compiler_core.compile_package(
		"examples/programs/expand", output, nil, target.DEFAULT, cimport.Options{}, ".",
	)
	testing.expect_value(t, status, 0)
	state, stdout, stderr, _ := os2.process_exec(
		os2.Process_Desc{command=[]string{output}}, context.allocator,
	)
	defer delete(stdout)
	defer delete(stderr)
	testing.expect_value(t, state.exit_code, 0)
	testing.expect_value(t, string(stdout), "")
	testing.expect_value(t, string(stderr), "")
}

@(test)
expanded_match_and_tag_diagnostics :: proc(t: ^testing.T) {
	text := `E :: enum { a, b }
Plain :: union { value i32 }

main func() void {
	inline for {1} |value| { _ = value }

	n i32 = 1
	match n { expand |value|: _ = value }

	e E = .a
	match e { expand |value, tag|: _ = value }
	match e {
		.a, .b: {}
		expand |value|: _ = value
	}
	match e {
		expand |value|: _ = value
		.b: {}
	}
	match e {
		else: {}
		expand |value|: _ = value
	}

	u Plain = Plain{value = 1}
	_ = tag!(u)
	_ = tagname!(e)

	match e { expand ||: {} }
	match e { expand |a, b, c|: {} }
}
`
	source_file := source.Source{path="expand_diagnostics.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_old := false
	found_subject := false
	found_captures := false
	found_redundant := false
	found_after := false
	found_missing := false
	found_many := false
	found_tag := false
	found_tagname := false
	for diagnostic in diagnostics.items {
		message := diagnostic.message
		found_old = found_old || strings.contains(message, "'inline for' was renamed to 'expand for'")
		found_subject = found_subject || strings.contains(message, "'expand' requires an enum or tagged-union")
		found_captures = found_captures || strings.contains(message, "requires exactly one capture")
		found_redundant = found_redundant || strings.contains(message, "redundant 'expand'")
		found_after = found_after || strings.contains(message, "arms after 'expand' are unreachable") || strings.contains(message, "arms after 'else' are unreachable")
		found_missing = found_missing || strings.contains(message, "expected an expand value capture")
		found_many = found_many || strings.contains(message, "at most two captures")
		found_tag = found_tag || strings.contains(message, "tag! requires a tagged-union value")
		found_tagname = found_tagname || strings.contains(message, "tagname! requires a comptime-known enum value")
	}
	testing.expect(t, found_old)
	testing.expect(t, found_subject)
	testing.expect(t, found_captures)
	testing.expect(t, found_redundant)
	testing.expect(t, found_after)
	testing.expect(t, found_missing)
	testing.expect(t, found_many)
	testing.expect(t, found_tag)
	testing.expect(t, found_tagname)
}

@(test)
milestone_37_format_errors_are_reported_at_comptime :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-format-errors"
	main_path := "/tmp/brolang-test-format-errors/main.bro"
	text := `io :: import "@std/io"
process :: import "@std/process"

main func(init process.Init) void {
	writer io.Writer :: io.stdout(init.io)
	stored :: typeinfo!(i32)
	_ = stored
	io.print(writer, "", 1) catch |_| {}
	io.print(writer, "{s}", {1,}) catch |_| {}
	io.print(writer, "{d}", {"bro",}) catch |_| {}
	io.print(writer, "{d}{d}", {1,}) catch |_| {}
	io.print(writer, "{d}", {1, 2}) catch |_| {}
	io.print(writer, "{q}", {}) catch |_| {}
	io.print(writer, "{b}", {1.5,}) catch |_| {}
	io.print(writer, "{e}", {1,}) catch |_| {}
	io.print(writer, "{c}", {i16(65),}) catch |_| {}
	io.print(writer, "}", {}) catch |_| {}
}
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))

	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	ast_module, loaded := loader.load(directory, &sources, &diagnostics, &symbols, project_root_path=".")
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := [10]bool{}
	for diagnostic in diagnostics.items {
		message := diagnostic.message
		found[0] = found[0] || strings.contains(message, "arguments must be a tuple")
		found[1] = found[1] || strings.contains(message, "cannot implicitly convert i8 to []u8")
		found[2] = found[2] || strings.contains(message, "'{d}' requires an integer or float")
		found[3] = found[3] || strings.contains(message, "argument count does not match")
		found[4] = found[4] || strings.contains(message, "unknown specifier")
		found[5] = found[5] || strings.contains(message, "unmatched '}'")
		found[6] = found[6] || strings.contains(message, "compile-time-only metadata")
		found[7] = found[7] || strings.contains(message, "integer format requires an integer argument")
		found[8] = found[8] || strings.contains(message, "float format requires a float argument")
		found[9] = found[9] || strings.contains(message, "'{c}' requires an unsigned integer that fits in u8")
	}
	testing.expect(t, loaded)
	for present in found {
		testing.expect(t, present)
	}
}

@(test)
milestone_39_stable_values_and_richer_formatting_compile_and_run :: proc(t: ^testing.T) {
	stable_names: [dynamic]string
	defer {
		for name in stable_names {
			delete(name)
		}
		delete(stable_names)
	}
	for pass := 0; pass < 2; pass += 1 {
		sources := source.init_store()
		diagnostics := source.init_store_diagnostics(&sources)
		symbols := symbol.init_table()
		ast_module, loaded := loader.load(
			"examples/programs/milestone_39", &sources, &diagnostics, &symbols, project_root_path=".",
		)
		hir_module := checker.check(&ast_module, &diagnostics, &symbols)
		ir_module := lower.lower(&hir_module)
		llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)

		score_count := 0
		for function in hir_module.functions {
			if strings.contains(function.link_name, "bro__p0__score__ca") {
				if pass == 0 {
					append(&stable_names, strings.clone(function.link_name))
				} else {
					testing.expect_value(t, function.link_name, stable_names[score_count])
				}
				score_count += 1
			}
		}
		testing.expect(t, loaded)
		testing.expect_value(t, len(diagnostics.items), 0)
		testing.expect_value(t, score_count, 2)
		testing.expect_value(t, count_substring_occurrences(llvm_text, "define internal fastcc i32 @bro__p0__read_carrier__"), 1)
		testing.expect(t, !strings.contains(llvm_text, "FormatToken"))
		testing.expect(t, !strings.contains(llvm_text, "parse_format"))
		testing.expect(t, !strings.contains(llvm_text, "FieldInfo"))
		testing.expect(t, !strings.contains(llvm_text, "EnumInfo"))

		delete(llvm_text)
		ir.destroy_module(&ir_module)
		hir.destroy_module(&hir_module)
		ast.destroy_module(&ast_module)
		symbol.destroy_table(&symbols)
		source.destroy_diagnostics(&diagnostics)
		source.destroy_store(&sources)
	}

	output := "/tmp/brolang-test-milestone-39"
	defer _ = os.remove(output)
	status := compiler_core.compile_package(
		"examples/programs/milestone_39", output, nil, target.DEFAULT, cimport.Options{}, ".",
	)
	testing.expect_value(t, status, 0)
	state, stdout, stderr, _ := os2.process_exec(
		os2.Process_Desc{command=[]string{output}}, context.allocator,
	)
	defer delete(stdout)
	defer delete(stderr)
	testing.expect_value(t, state.exit_code, 0)
	testing.expect_value(
		t,
		string(stdout),
		"true -42 1.5 .running bro 2.5 1010 12 ff FF A 1.5000000000000000e+00 {} -9223372036854775808 0 inf nan 1.50000000e+00\n",
	)
	testing.expect_value(t, string(stderr), "debug=.idle 2a\n")
}

@(test)
milestone_39_rejects_values_without_stable_identity :: proc(t: ^testing.T) {
	text := `BadUnion :: union { number i32, flag bool }
Config :: struct { value i32 }

identity func() i32 { return 1 }
reject_pointer func($value @i32) void {}
reject_function func($value @func() i32) void {}
reject_slice func($value []i32) void {}
reject_range func($value range) void {}
reject_union func($value BadUnion) void {}
reject_undefined func($value Config) void {}

stored i32 :: 1
items [2]i32 :: [1, 2]

main func() void {
	reject_pointer(&stored)
	reject_function(identity)
	reject_slice(items[..])
	reject_range(0..3)
	reject_union(BadUnion {number = 1})
	reject_undefined(Config {value = undefined})
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := 0
	for diagnostic in diagnostics.items {
		if strings.contains(diagnostic.message, "comptime argument has no stable comptime identity") {
			found += 1
		}
	}
	testing.expect(t, found >= 6)
}

@(test)
milestone_37_expand_loop_control_must_be_statically_resolvable :: proc(t: ^testing.T) {
	text := `main func() void {
	total i32 = 0
	expand for {1, 2} |value| {
		if total == 0 {
			break
		}
		total += value
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(
			diagnostic.message,
			"break or continue targeting an expand loop must be compile-time-resolvable",
		)
	}
	testing.expect(t, found)
}

@(test)
milestone_37_comptime_undefined_aggregates_support_full_initialization :: proc(t: ^testing.T) {
	text := `Token :: struct {
	text []u8
	count usize
}
Partial :: struct { initialized i32, text []u8 }
make_tokens func() [2]mut Token {
	tokens [2]mut Token = undefined
	tokens[0] = Token {text = "a", count = 1}
	tokens[1].text = "bro"
	tokens[1].count = 3
	return tokens
}
read_initialized_sibling func() i32 {
	value Partial = undefined
	value.initialized = 42
	return value.initialized
}
answer :: $read_initialized_sibling()
main func() i32 {
	total usize = 0
	expand for make_tokens() |token| {
		total += token.text.len + token.count
	}
	if answer != 42 or total != 8 {
		return 1
	}
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
milestone_37_comptime_undefined_values_cannot_be_observed :: proc(t: ^testing.T) {
	text := `Bad :: struct { value i32, text []u8 }
read_scalar func() i32 {
	value i32 = undefined
	return value
}
return_partial func() Bad {
	value Bad = undefined
	value.value = 1
	return value
}
take_bad func(value Bad) i32 {
	return value.value
}
pass_partial func() i32 {
	value Bad = undefined
	value.value = 1
	return take_bad(value)
}
bad_scalar :: $read_scalar()
bad_record :: $return_partial()
bad_argument :: $pass_partial()
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_read := false
	found_return := false
	found_pass := false
	for diagnostic in diagnostics.items {
		found_read = found_read || strings.contains(diagnostic.message, "cannot read an undefined value at comptime")
		found_return = found_return || strings.contains(diagnostic.message, "comptime function returned an undefined value")
		found_pass = found_pass || strings.contains(diagnostic.message, "cannot pass an undefined value at comptime")
	}
	testing.expect(t, found_read)
	testing.expect(t, found_return)
	testing.expect(t, found_pass)
}

@(test)
milestone_37_expand_expansions_keep_distinct_call_resolutions :: proc(t: ^testing.T) {
	text := `identity func($T type, value T) T {
	return value
}
main func() i32 {
	total i64 = 0
	expand for {{i8(1), i16(2)}, {i32(3), i64(4)}} |row| {
		expand for row |value| {
			total += i64(identity(value))
		}
	}
	return i32(total - 10)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	identity_symbol := symbol.intern(&symbols, "identity")
	specializations := 0
	for function in hir_module.functions {
		specializations += 1 if function.name == identity_symbol else 0
	}
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, specializations, 4)
}

@(test)
milestone_37_expand_control_prunes_inference_after_static_exit :: proc(t: ^testing.T) {
	text := `take_i8 func(value i8) void { _ = value }
main func() void {
	expand for {i8(1), "skip"} |value, index| {
		if index == 1 {
			continue
		}
		take_i8(value)
	}
	expand for {i8(1), "stop"} |value, index| {
		if index == 1 {
			break
		}
		take_i8(value)
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
milestone_37_expand_match_specialization_prunes_unselected_arms :: proc(t: ^testing.T) {
	text := `Kind :: enum { integer, string, stop }
IntToken :: struct { kind Kind, value i8 }
StringToken :: struct { kind Kind, value []u8 }
StopToken :: struct { kind Kind, value bool }
take_i8 func(value i8) void { _ = value }
main func() void {
	expand for {
		IntToken {kind = .integer, value = 1},
		StringToken {kind = .string, value = "ok"},
		StopToken {kind = .stop, value = false},
	} |token| {
		match token.kind {
			.integer: take_i8(token.value)
			.string: {
				_ = token.value.len
				continue
			}
			.stop: break
		}
	}
	expand for {i8(2), "skip", "stop"} |value, index| {
		match index {
			0: {}
			1..=1, 7: continue
			else: break
		}
		take_i8(value)
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
milestone_33_rejects_an_incompatible_runtime_write_declaration :: proc(t: ^testing.T) {
	text := `write c_func(_ c_int, _ c_int, _ c_ulong) c_long
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(
			diagnostic.message,
			"external C function 'write' conflicts with the compiler runtime declaration",
		)
	}
	testing.expect(t, found)
}

@(test)
literal_addition_trees_fold_with_contextual_types :: proc(t: ^testing.T) {
	text := `return_i16 func() i16 {
	return 1 + 2
}
take_i16 func(value i16) i16 {
	return value
}
take_int func(value int) int {
	return value
}
main func() void {
	local i16 :: 1 + 2
	_ = local
	_ = 100 + (20 + 8)
	_ = return_i16()
	_ = take_i16(1 + 2)
	_ = take_int(127 + 1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "@bro__p0__take_int__i16"))
	for function in ir_module.functions {
		for instruction in function.instructions {
			testing.expect(t, instruction.op != ir.Opcode.Add_Checked)
		}
	}

	for function in hir_module.functions {
		for statement_id in function.body {
			statement := hir_module.statements[statement_id]
			if statement.expr < 0 {
				continue
			}
			expr := hir_module.exprs[statement.expr]
			if expr.kind == .Integer {
				testing.expect(t, types.equal(expr.type, types.I16))
			}
			if expr.kind == .Call && symbol.resolve(&symbols, function.name) == "main" && len(expr.args) > 0 {
				arg := hir_module.exprs[expr.args[0]]
				testing.expect_value(t, arg.kind, hir.Expr_Kind.Integer)
				testing.expect(t, types.equal(arg.type, types.I16))
			}
		}
	}
}

@(test)
runtime_arithmetic_does_not_inherit_result_context :: proc(t: ^testing.T) {
	text := `widen_after_add func(value i8) i16 {
	return value + 1
}
main func() void {
	_ = widen_after_add(1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	found := false
	for function in hir_module.functions {
		if symbol.resolve(&symbols, function.name) != "widen_after_add" {
			continue
		}
		found = true
		statement := hir_module.statements[function.body[0]]
		widen := hir_module.exprs[statement.expr]
		add := hir_module.exprs[widen.left]
		testing.expect_value(t, widen.kind, hir.Expr_Kind.Widen)
		testing.expect(t, types.equal(widen.type, types.I16))
		testing.expect_value(t, add.kind, hir.Expr_Kind.Add)
		testing.expect(t, types.equal(add.type, types.I8))
	}
	testing.expect(t, found)
}

@(test)
parser_recovers_after_invalid_tokens :: proc(t: ^testing.T) {
	text := `broken @ declaration
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect(t, len(diagnostics.items) > 0)
	testing.expect_value(t, len(module.functions), 1)
	testing.expect_value(t, symbol.resolve(&symbols, module.functions[0].name), "main")
}

@(test)
return_sink_and_unconsumed_values_have_distinct_hir :: proc(t: ^testing.T) {
	text := `give func() i8 {
	return 1
}
done func() void {
	return
}
main func() void {
	done()
	_ = give()
	give()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	done_id, main_id := -1, -1
	for function, id in hir_module.functions {
		if symbol.resolve(&symbols, function.name) == "done" {
			done_id = id
		} else if symbol.resolve(&symbols, function.name) == "main" {
			main_id = id
		}
	}
	testing.expect(t, done_id >= 0)
	testing.expect(t, main_id >= 0)
	testing.expect_value(t, hir_module.statements[hir_module.functions[done_id].body[0]].kind, hir.Stmt_Kind.Return)
	testing.expect_value(t, hir_module.statements[hir_module.functions[done_id].body[0]].expr, hir.INVALID_EXPR)
	main := hir_module.functions[main_id]
	testing.expect_value(t, hir_module.statements[main.body[0]].kind, hir.Stmt_Kind.Expression)
	testing.expect_value(t, hir_module.statements[main.body[1]].kind, hir.Stmt_Kind.Sink)
	testing.expect_value(t, hir_module.statements[main.body[2]].kind, hir.Stmt_Kind.Trap)
}

@(test)
bare_returns_and_strict_yields :: proc(t: ^testing.T) {
	text := `Failure :: enum { bad }
noop func() void {}
newline_return func() void {
	return
}
inline_return func() void { return }
fallible_return func() void ! Failure { return }
split_return func() i32 {
	return
	1
}
old_return func() void { return _ }
missing_yield func() i32 {
	value :: {
		yield
		1
	}
	return value
}
missing_labeled_yield func() i32 {
	value :: block: {
		yield :block
	}
	return value
}
void_yield func() i32 {
	value :: { yield noop() }
	return value
}
sink_yield func() i32 {
	value :: { yield _ }
	return value
}
void_context func() void {
	fallible_return() catch |_| { yield 1 }
}
bad_comptime :: ${ yield noop() }
main func() void {
	newline_return()
	inline_return()
	fallible_return() catch |_| {}
	_ = split_return()
	old_return()
	_ = missing_yield()
	_ = missing_labeled_yield()
	_ = void_yield()
	_ = sink_yield()
	void_context()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, ast_module.statements[ast_module.functions[1].body[0]].expr, ast.INVALID_EXPR)
	testing.expect_value(t, ast_module.statements[ast_module.functions[2].body[0]].expr, ast.INVALID_EXPR)
	testing.expect_value(t, ast_module.statements[ast_module.functions[3].body[0]].expr, ast.INVALID_EXPR)
	testing.expect_value(t, len(ast_module.functions[4].body), 2)

	missing_value := false
	non_void_function := false
	void_yields := 0
	sink_read := false
	void_context := false
	for diagnostic in diagnostics.items {
		missing_value = missing_value || strings.contains(diagnostic.message, "'yield' must produce a value")
		non_void_function = non_void_function || strings.contains(diagnostic.message, "non-void function must return a value")
		if strings.contains(diagnostic.message, "'yield' expression must produce a non-void value") {
			void_yields += 1
		}
		sink_read = sink_read || strings.contains(diagnostic.message, "'_' is a write-only sink and cannot be read")
		void_context = void_context || strings.contains(diagnostic.message, "void value context must fall through instead of yielding")
	}
	testing.expect(t, missing_value)
	testing.expect(t, non_void_function)
	testing.expect(t, void_yields >= 2)
	testing.expect(t, sink_read)
	testing.expect(t, void_context)
}

@(test)
unused_locals_and_params_warn_without_traps :: proc(t: ^testing.T) {
	text := `warn_only func(value i32, unused i32) i32 {
	local i32 = 1
	write_only i32 = 2
	write_only = 3
	consumed i32 = value
	_ = consumed
	return value
}
main func() void {
	_ = warn_only(1, 2)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_unused_param := false
	found_unused_local := false
	found_write_only := false
	warning_count := 0
	error_count := 0
	for diagnostic in diagnostics.items {
		if diagnostic.severity == source.Severity.Warning {
			warning_count += 1
		} else {
			error_count += 1
		}
		found_unused_param = found_unused_param || strings.contains(diagnostic.message, "unused parameter 'unused'")
		found_unused_local = found_unused_local || strings.contains(diagnostic.message, "unused local 'local'")
		found_write_only = found_write_only || strings.contains(diagnostic.message, "unused local 'write_only'")
		testing.expect(t, !strings.contains(diagnostic.message, "unused local 'consumed'"))
		testing.expect(t, !strings.contains(diagnostic.message, "unused parameter 'value'"))
	}
	testing.expect_value(t, warning_count, 3)
	testing.expect_value(t, error_count, 0)
	testing.expect(t, found_unused_param)
	testing.expect(t, found_unused_local)
	testing.expect(t, found_write_only)

	found_function := false
	for function in hir_module.functions {
		if symbol.resolve(&symbols, function.name) != "warn_only" {
			continue
		}
		found_function = true
		testing.expect(t, !function.problematic)
		for stmt_id in function.body {
			testing.expect(t, hir_module.statements[stmt_id].kind != hir.Stmt_Kind.Trap)
		}
	}
	testing.expect(t, found_function)
}

@(test)
generic_parameter_usage_is_source_based :: proc(t: ^testing.T) {
	text := `choose func($N usize, used, unused i32) i32 {
	if N > 0 {
		return used
	}
	return 0
}
main func() void {
	_ = choose(0, 1, 2)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 1)
	testing.expect_value(t, diagnostics.items[0].severity, source.Severity.Warning)
	testing.expect(t, strings.contains(diagnostics.items[0].message, "unused parameter 'unused'"))
	testing.expect(t, !strings.contains(diagnostics.items[0].message, "unused parameter 'used'"))
}

@(test)
recursive_specialization_reaches_a_fixed_point :: proc(t: ^testing.T) {
	text := `a func(value int) i32 {
	return b(value)
}
b func(value int) i32 {
	return a(value)
}
main func() void {
	_ = a(1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(hir_module.functions), 3)
}

@(test)
stale_specializations_are_pruned_after_inference :: proc(t: ^testing.T) {
	text := `derived :: identity(make())
wide :: delayed()
identity func(value int) int {
	return value
}
make func() int {
	return wide
	return 1
}
delayed func() int {
	return 128
}
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(hir_module.functions), 4)
	testing.expect(t, strings.contains(llvm_text, "@bro__p0__identity__i16"))
	testing.expect(t, !strings.contains(llvm_text, "@bro__p0__identity__i8"))
}

@(test)
eager_global_calls_root_specializations :: proc(t: ^testing.T) {
	text := `make func() i32 {
	return 7
}
unused_native func() i32 {
	return 9
}
unused_foreign c_func() i32
value i32 :: make()
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(hir_module.functions), 2)
	testing.expect(t, strings.contains(llvm_text, "@bro__p0__make("))
	testing.expect(t, !strings.contains(llvm_text, "@bro__p0__unused_native("))
	testing.expect(t, !strings.contains(llvm_text, "@unused_foreign("))
}

@(test)
malformed_generic_calls_do_not_retain_specializations :: proc(t: ^testing.T) {
	text := `identity func(value int) int {
	return value
}
bad :: identity(1, 2)
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	found_arity := false
	for diagnostic in diagnostics.items {
		found_arity = found_arity || strings.contains(diagnostic.message, "expects 1 arguments, got 2")
	}
	testing.expect(t, found_arity)
	testing.expect_value(t, len(hir_module.functions), 1)
	testing.expect(t, !strings.contains(llvm_text, "@bro__p0__identity"))
	testing.expect(t, strings.contains(llvm_text, "call void @bro.trap"))
}

@(test)
long_generic_call_chain_reaches_a_fixed_point :: proc(t: ^testing.T) {
	builder := strings.builder_make()
	defer strings.builder_destroy(&builder)
	for index in 0 ..< 70 {
		fmt.sbprintf(&builder, "fn%d func(value int) int ", index)
		strings.write_string(&builder, "{ return ")
		if index == 69 {
			strings.write_string(&builder, "value")
		} else {
			fmt.sbprintf(&builder, "fn%d(value)", index+1)
		}
		strings.write_string(&builder, " }\n")
	}
	strings.write_string(&builder, "main func() i32 { return fn0(1) }\n")

	source_file := source.Source{path="test.bro", text=strings.to_string(builder)}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(hir_module.functions), 71)
}

@(test)
globals_and_generic_results_reach_a_shared_fixed_point :: proc(t: ^testing.T) {
	text := `derived :: identity(base)
base :: make()
identity func(value int) int {
	return value
}
make func() int {
	return 1
}
main func() i32 {
	return derived
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(hir_module.functions), 3)
	testing.expect(t, types.equal(hir_module.globals[0].type, types.I32))
	testing.expect(t, types.equal(hir_module.globals[1].type, types.I8))
}

@(test)
comptime_value_params_specialize_by_value_and_omit_runtime_args :: proc(t: ^testing.T) {
	text := `make_array func($N usize) [N]u8 {
	data [N]u8 = undefined
	return data
}
main func() void {
	four [_]u8 :: make_array(4)
	eight [_]u8 :: make_array(8)
	again [_]u8 :: make_array(4)
	literal [_]u8 :: [1, 2, 3, 4]
	_ = four
	_ = eight
	_ = again
	_ = literal
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	make_specs := 0
	for function in hir_module.functions {
		if symbol.resolve(&symbols, function.name) == "make_array" {
			make_specs += 1
			testing.expect_value(t, len(function.params), 0)
		}
	}

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, make_specs, 2)
	testing.expect(t, strings.contains(llvm_text, "@bro__p0__make_array__cv4"))
	testing.expect(t, strings.contains(llvm_text, "@bro__p0__make_array__cv8"))
}

@(test)
comptime_value_params_diagnose_invalid_uses :: proc(t: ^testing.T) {
	text := `make func($N usize) i32 {
	return N
}
tiny func($N u8) i32 {
	return N
}
good_bool func($T bool) void {}
bad_use func($N usize) void {
	N = 1
	_ = &N
}
main func() void {
	good_bool(true)
	x usize = 4
	_ = make(x)
	_ = make()
	_ = make(1, 2)
	_ = make(-1)
	_ = tiny(300)
	bad_use(4)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_runtime_arg := false
	found_missing := false
	found_extra := false
	found_negative := false
	found_range := false
	found_assignment := false
	found_address := false
	for diagnostic in diagnostics.items {
		message := diagnostic.message
		found_runtime_arg = found_runtime_arg || strings.contains(message, "must be a compile-time integer expression")
		found_missing = found_missing || strings.contains(message, "cannot infer comptime parameter 'N'")
		found_extra = found_extra || strings.contains(message, "has no unique complete argument mapping")
		found_negative = found_negative || strings.contains(message, "integer constant -1 does not fit in usize")
		found_range = found_range || strings.contains(message, "integer constant 300 does not fit in u8")
		found_assignment = found_assignment || strings.contains(message, "cannot assign comptime parameter 'N'")
		found_address = found_address || strings.contains(message, "'&' requires an addressable location")
	}

	testing.expect(t, found_runtime_arg)
	testing.expect(t, found_missing)
	testing.expect(t, found_extra)
	testing.expect(t, found_negative)
	testing.expect(t, found_range)
	testing.expect(t, found_assignment)
	testing.expect(t, found_address)
}

@(test)
inferred_comptime_params_diagnose_ambiguous_calls :: proc(t: ^testing.T) {
	text := `Ignored func($T type) type {
	return i32
}
Box func($T type) type {
	return struct { value T }
}
BoxAlias func($T type) type {
	return Box(T)
}
conflict func($T type, left, right T) T { return left }
unknown func($T type) T { value T = undefined; return value }
partial func($T type, $N usize, value T) T { return value }
use_ignored func($T type, value Ignored(T)) i32 { return value }
use_alias func($T type, value BoxAlias(T)) T { return value.value }
mapping_fail func($A usize, value i32, $B usize) void {}
main func() void {
	a i32 :: 1
	b u32 :: 2
	_ = conflict(a, b)
	_ = unknown()
	_ = partial(i32, a)
	_ = use_ignored(a)
	box Box(i32) :: Box(i32) { value = 1 }
	_ = use_alias(box)
	mapping_fail(true, false)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_conflict := false
	found_unknown := false
	found_partial := false
	found_candidate_failures := false
	unrecoverable := 0
	for diagnostic in diagnostics.items {
		message := diagnostic.message
		found_conflict = found_conflict || strings.contains(message, "conflicting inference for comptime parameter 'T': i32 and u32")
		found_unknown = found_unknown || strings.contains(message, "cannot infer comptime parameter 'T'")
		found_partial = found_partial || strings.contains(message, "cannot infer comptime parameter 'N'")
		found_candidate_failures = found_candidate_failures ||
			strings.contains(message, "candidate 1: cannot infer comptime parameter 'B'") &&
			strings.contains(message, "candidate 2: cannot infer comptime parameter 'A'")
		if strings.contains(message, "cannot infer comptime parameter 'T'") {
			unrecoverable += 1
		}
	}
	testing.expect(t, found_conflict)
	testing.expect(t, found_unknown)
	testing.expect(t, found_partial)
	testing.expect(t, found_candidate_failures)
	testing.expect(t, unrecoverable >= 3)
}

@(test)
comptime_params_may_be_interleaved_and_are_erased_from_the_abi :: proc(t: ^testing.T) {
	text := `valid func($T type, $N usize, value T) [N]T {
	result [N]T = undefined
	_ = value
	return result
}
runtime_first func(value T, $T type, $N usize) T { return value }
split func($T type, value T, $N usize) [N]T {
	result [N]T = undefined
	_ = value
	return result
}
from_result func($T type) T {
	value T = undefined
	return value
}
choose_mapping func($A usize, value i32, $B usize) [A]u8 {
	result [A]u8 = undefined
	_ = value
	_ = B
	return result
}
main func() void {
	_ = runtime_first(42, i32, 4)
	_ = runtime_first(42, _, 4)
	_ = split(i32, 42, 4)
	_ = split(42, 4)
	value i32 = from_result()
	chosen [1]u8 :: choose_mapping(7, 2)
	_ = value
	_ = chosen
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	for function in hir_module.functions {
		name := symbol.resolve(&symbols, function.name)
		if name == "runtime_first" || name == "split" {
			testing.expect_value(t, len(function.params), 1)
		} else if name == "from_result" {
			testing.expect_value(t, len(function.params), 0)
		} else if name == "choose_mapping" {
			testing.expect_value(t, len(function.params), 1)
		}
	}
	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
comptime_type_params_specialize_by_type_and_omit_runtime_args :: proc(t: ^testing.T) {
	text := `Point :: struct {
	x i32
}
id func($T type, value T) T {
	return value
}
zero func($T type) T {
	value T = undefined
	return value
}
buffer func($T type, $N usize, _ T) [N]T {
	data [N]T = undefined
	return data
}
main func() void {
	a i32 :: 42
	b u8 :: 7
	p Point :: Point { x = 9 }
	_ = id(i32, a)
	_ = id(u8, b)
	_ = id(Point, p)
	_ = zero(i32)
	_ = buffer(u8, 4, b)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	id_specs := 0
	zero_specs := 0
	buffer_specs := 0
	for function in hir_module.functions {
		name := symbol.resolve(&symbols, function.name)
		if name == "id" {
			id_specs += 1
			testing.expect_value(t, len(function.params), 1)
		} else if name == "zero" {
			zero_specs += 1
			testing.expect_value(t, len(function.params), 0)
		} else if name == "buffer" {
			buffer_specs += 1
			testing.expect_value(t, len(function.params), 1)
		}
	}

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, id_specs, 3)
	testing.expect_value(t, zero_specs, 1)
	testing.expect_value(t, buffer_specs, 1)
	testing.expect(t, strings.contains(llvm_text, "@bro__p0__id__i32__cti32"))
	testing.expect(t, strings.contains(llvm_text, "@bro__p0__zero__cti32"))
	testing.expect(t, strings.contains(llvm_text, "@bro__p0__buffer__u8__ctu8__cv4"))
}

@(test)
comptime_type_params_diagnose_invalid_uses :: proc(t: ^testing.T) {
	text := `id func($T type, value T) T {
	return value
}
bad_c c_func($T type) void
bad_value func($T type) void {
	_ = T
}
bad_assign func($T type) void {
	T = 1
}
main func() void {
	x i32 = 1
	_ = id(x, x)
	bad_value(i32)
	bad_assign(i32)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_arg := false
	found_c_func := false
	found_value := false
	found_assign := false
	for diagnostic in diagnostics.items {
		message := diagnostic.message
		found_arg = found_arg || strings.contains(message, "argument for comptime type parameter 'T' must be a type")
		found_c_func = found_c_func || strings.contains(message, "comptime parameters require 'func', not 'c_func'")
		found_value = found_value || strings.contains(message, "type parameter 'T' is not a runtime value")
		found_assign = found_assign || strings.contains(message, "cannot assign comptime parameter 'T'")
	}

	testing.expect(t, found_arg)
	testing.expect(t, found_c_func)
	testing.expect(t, found_value)
	testing.expect(t, found_assign)
}

@(test)
comptime_expression_forces_integer_evaluation :: proc(t: ^testing.T) {
	text := `sum func(a, b int) int {
	return a + b
}
max func(a, b int) int {
	if a > b {
		return a
	}
	return b
}
nested func(value int) int {
	two :: 2
	return sum(value, two)
}
make_array func($N usize) [N]u8 {
	data [N]u8 = undefined
	return data
}
forced :: $sum(1, 2)
main func() i32 {
	value i32 :: $sum(20, 22)
	choice i32 :: $max(9, 3)
	blocked i32 :: ${
		local :: 5
		yield sum(local, 6)
	}
	bytes [_]u8 :: make_array($nested(2))
	if forced != 3 {
		return 1
	}
	if value != 42 {
		return 2
	}
	if choice != 9 {
		return 3
	}
	if blocked != 11 {
		return 4
	}
	if bytes.len != 4 {
		return 5
	}
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "@bro.g.0 = internal constant i8 3"))
}

@(test)
comptime_expression_diagnoses_runtime_only_and_quota :: proc(t: ^testing.T) {
	text := `native c_func() i32
spin func() i32 {
	while true {
	}
	return 0
}
missing func() i32 {
	if true {
	}
}
GLOBAL :: 1
main func() void {
	runtime i32 = 1
	_ = $runtime
	_ = $native()
	_ = ${
		callback :: native
		yield callback()
	}
	_ = $&GLOBAL
	_ = $spin()
	_ = $missing()
	_ = ${
		value :: 1
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_runtime := false
	runtime_only_count := 0
	found_pointer := false
	found_quota := false
	found_missing := false
	found_yield := false
	for diagnostic in diagnostics.items {
		message := diagnostic.message
		found_runtime = found_runtime || strings.contains(message, "unresolved comptime value 'runtime'")
		runtime_only_count += 1 if strings.contains(message, "runtime-only") else 0
		found_pointer = found_pointer || strings.contains(message, "comptime storage pointers and slices cannot materialize as runtime memory")
		found_quota = found_quota || strings.contains(message, "comptime evaluation exceeded the step quota")
		found_missing = found_missing || strings.contains(message, "did not return a value")
		found_yield = found_yield || strings.contains(message, "comptime block must yield a value")
	}
	testing.expect(t, found_runtime)
	testing.expect(t, runtime_only_count >= 2)
	testing.expect(t, found_pointer)
	testing.expect(t, found_quota)
	testing.expect(t, found_missing)
	testing.expect(t, found_yield)
}

@(test)
native_function_pointer_type_restrictions_are_diagnosed :: proc(t: ^testing.T) {
	text := `main func() void {
	callback @func(...) void = undefined
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_variadic := false
	for diagnostic in diagnostics.items {
		found_variadic =
			found_variadic ||
			strings.contains(diagnostic.message, "native function pointer types do not support variadic parameters")
	}
	testing.expect(t, found_variadic)
}

@(test)
unused_function_signatures_are_validated_eagerly :: proc(t: ^testing.T) {
	text := `broken func(value, value i8, nope void) void {}
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_duplicate := false
	found_void := false
	for diagnostic in diagnostics.items {
		found_duplicate = found_duplicate || strings.contains(diagnostic.message, "duplicate parameter 'value'")
		found_void = found_void || strings.contains(diagnostic.message, "void is only valid as a function result type")
	}
	testing.expect(t, found_duplicate)
	testing.expect(t, found_void)
}

run_command_success :: proc(command: []string) -> bool {
	state, stdout, stderr, err := os2.process_exec(
		os2.Process_Desc{command=command},
		context.allocator,
	)
	delete(stdout)
	delete(stderr)
	return err == nil && state.exit_code == 0
}

prepare_native_object :: proc(output: string) -> bool {
	local_cache := fmt.aprintf("ZIG_LOCAL_CACHE_DIR=%s-zig-cache", output)
	defer delete(local_cache)
	global_cache := fmt.aprintf("ZIG_GLOBAL_CACHE_DIR=%s-zig-global-cache", output)
	defer delete(global_cache)
	return run_command_success([]string{
		"/usr/bin/env",
		local_cache,
		global_cache,
		"zig",
		"cc",
		"-c",
		"examples/interop/manual/native.c",
		"-o",
		output,
	})
}

prepare_native_archive :: proc(object, archive: string) -> bool {
	return run_command_success([]string{
		"/usr/bin/ar",
		"-rcs",
		archive,
		object,
	})
}

run_executable :: proc(path: string) -> os2.Process_State {
	state, stdout, stderr, _ := os2.process_exec(
		os2.Process_Desc{command=[]string{path}},
		context.allocator,
	)
	delete(stdout)
	delete(stderr)
	return state
}

@(test)
valid_program_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-valid"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/prototype", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
unused_local_warnings_return_status_one_but_do_not_trap :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-unused-locals"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/unused_locals", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 7)
}

@(test)
build_command_is_recognized :: proc(t: ^testing.T) {
	testing.expect(t, is_build_command("build"))
	testing.expect(t, !is_build_command("translate-c"))
	testing.expect(t, !is_build_command("--build"))
}

@(test)
version_command_is_recognized :: proc(t: ^testing.T) {
	testing.expect(t, is_version_command("version"))
	testing.expect(t, !is_version_command("--version"))
	testing.expect(t, len(BROLANG_VERSION) > 0)
}

@(test)
build_subcommand_compiles_and_runs :: proc(t: ^testing.T) {
	output := "examples/build/hello/build/hello"
	defer _ = os2.remove_all("examples/build/hello/build")
	status := compiler_core.run_build("examples/build/hello")
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
	status = compiler_core.run_build("examples/build/hello")
	testing.expect_value(t, status, 0)
	testing.expect(t, os.exists(output))
}

@(test)
build_subcommand_links_c_source_via_list_field :: proc(t: ^testing.T) {
	output := "examples/build/manual/build/manual_build"
	defer _ = os2.remove_all("examples/build/manual/build")
	status := compiler_core.run_build("examples/build/manual")
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
new_project_creates_layout_and_builds :: proc(t: ^testing.T) {
	root := "/tmp/brolang-test-new-project"
	output := "/tmp/brolang-test-new-project/build/brolang-test-new-project"
	_ = os2.remove_all(root)
	defer _ = os2.remove_all(root)

	testing.expect_value(t, run_new_project(root), 0)
	testing.expect(t, os.is_dir("/tmp/brolang-test-new-project/source"))
	testing.expect(t, os.is_dir("/tmp/brolang-test-new-project/std"))
	testing.expect(t, os.is_dir("/tmp/brolang-test-new-project/ffi"))
	testing.expect(t, os.is_dir("/tmp/brolang-test-new-project/vendor"))
	testing.expect(t, os.exists("/tmp/brolang-test-new-project/build.bro"))
	testing.expect(t, os.exists("/tmp/brolang-test-new-project/source/main.bro"))

	status := compiler_core.run_build(root)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
init_project_creates_missing_layout_and_preserves_existing_files :: proc(t: ^testing.T) {
	root := "/tmp/brolang-test-init-project"
	output := "/tmp/brolang-test-init-project/build/brolang-test-init-project"
	_ = os2.remove_all(root)
	defer _ = os2.remove_all(root)

	testing.expect(t, os2.make_directory_all(root) == nil)
	testing.expect(t, init_project(root))
	testing.expect(t, os.is_dir("/tmp/brolang-test-init-project/source"))
	testing.expect(t, os.is_dir("/tmp/brolang-test-init-project/std"))
	testing.expect(t, os.is_dir("/tmp/brolang-test-init-project/ffi"))
	testing.expect(t, os.is_dir("/tmp/brolang-test-init-project/vendor"))

	status := compiler_core.run_build(root)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)

	custom_build := "custom build"
	custom_main := "custom main"
	testing.expect(t, os.write_entire_file("/tmp/brolang-test-init-project/build.bro", transmute([]byte)custom_build))
	testing.expect(t, os.write_entire_file("/tmp/brolang-test-init-project/source/main.bro", transmute([]byte)custom_main))
	testing.expect(t, init_project(root))
	build_data, build_ok := os.read_entire_file("/tmp/brolang-test-init-project/build.bro")
	defer delete(build_data)
	main_data, main_ok := os.read_entire_file("/tmp/brolang-test-init-project/source/main.bro")
	defer delete(main_data)
	testing.expect(t, build_ok && string(build_data) == custom_build)
	testing.expect(t, main_ok && string(main_data) == custom_main)
}

@(test)
build_root_search_finds_nearest_parent_build_file :: proc(t: ^testing.T) {
	root := "/tmp/brolang-test-build-search"
	nested := "/tmp/brolang-test-build-search/source/nested"
	_ = os2.remove_all(root)
	defer _ = os2.remove_all(root)

	testing.expect(t, os2.make_directory_all(nested) == nil)
	build_text := "# root\n"
	testing.expect(t, os.write_entire_file("/tmp/brolang-test-build-search/build.bro", transmute([]byte)build_text))
	found, ok := compiler_core.find_build_root_from(nested)
	defer delete(found)
	testing.expect(t, ok)
	testing.expect(t, strings.has_suffix(found, "/brolang-test-build-search"))
}

@(test)
build_subcommand_discovered_root_writes_to_root_build_dir :: proc(t: ^testing.T) {
	root := "/tmp/brolang-test-build-nested"
	nested := "/tmp/brolang-test-build-nested/source/nested"
	output := "/tmp/brolang-test-build-nested/build/brolang-test-build-nested"
	_ = os2.remove_all(root)
	defer _ = os2.remove_all(root)

	testing.expect(t, init_project(root))
	testing.expect(t, os2.make_directory_all(nested) == nil)
	found, ok := compiler_core.find_build_root_from(nested)
	defer delete(found)
	testing.expect(t, ok)

	status := compiler_core.run_build(found)
	testing.expect_value(t, status, 0)
	testing.expect(t, os.exists(output))
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
build_subcommand_rejects_path_like_output_name :: proc(t: ^testing.T) {
	root := "/tmp/brolang-test-build-invalid-name"
	_ = os2.remove_all(root)
	defer _ = os2.remove_all(root)

	testing.expect(t, init_project(root))
	text := `b :: import "@std/build"

config :: b.BuildConfig{
	name = "bad/name",
	source = "source",
	libraries = &[],
	lib_paths = &[],
	includes = &[],
	defines = &[],
	links = &[],
}
`
	testing.expect(t, os.write_entire_file("/tmp/brolang-test-build-invalid-name/build.bro", transmute([]byte)text))
	status := compiler_core.run_build(root)
	testing.expect_value(t, status, 2)
	testing.expect(t, !os.exists("/tmp/brolang-test-build-invalid-name/build/bad/name"))
}

@(test)
project_root_imports_resolve_under_passed_root :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)

	ast_module, loaded := loader.load(
		"examples/build/raylib/source",
		&sources,
		&diagnostics,
		&symbols,
		context.allocator,
		context.allocator,
		cimport.Options{},
		target.DEFAULT,
		"examples/build/raylib",
	)
	defer ast.destroy_module(&ast_module)
	testing.expect(t, loaded)

	found_vendor := false
	for pkg in ast_module.packages {
		found_vendor = found_vendor || strings.has_suffix(pkg.path, "/examples/build/raylib/vendor/raylib")
	}
	testing.expect(t, found_vendor)
}

@(test)
direct_compile_defaults_project_root_to_input_package_and_allows_override :: proc(t: ^testing.T) {
	root := "/tmp/brolang-test-direct-root"
	app := "/tmp/brolang-test-direct-root/app"
	dep := "/tmp/brolang-test-direct-root/dep"
	output := "/tmp/brolang-test-direct-root-out"
	_ = os2.remove_all(root)
	_ = os.remove(output)
	defer _ = os2.remove_all(root)
	defer _ = os.remove(output)

	testing.expect(t, os2.make_directory_all(app) == nil)
	testing.expect(t, os2.make_directory_all(dep) == nil)
	main_text := "dep :: import \"@dep\"\nmain func() i32 { return dep.value }\n"
	dep_text := "value i32 :: 7\n"
	testing.expect(t, os.write_entire_file("/tmp/brolang-test-direct-root/app/main.bro", transmute([]byte)main_text))
	testing.expect(t, os.write_entire_file("/tmp/brolang-test-direct-root/dep/dep.bro", transmute([]byte)dep_text))

	testing.expect_value(t, compiler_core.compile_package(app, output), 1)
	status := compiler_core.compile_package(app, output, nil, target.DEFAULT, cimport.Options{}, root)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 7)
}

@(test)
c_printf_accepts_a_string_literal :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-printf"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/interop/printf", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
sentinel_pointer_views_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-sentinel-pointer"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/sentinel_pointer", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 303)
}

@(test)
milestone_24_regressions_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-milestone-24"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/milestone_24", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
milestone_24_rejects_invalid_forms :: proc(t: ^testing.T) {
	Case :: struct {
		directory: string,
		output:    string,
	}
	cases := [?]Case{
		{"examples/programs/index_signed_error", "/tmp/brolang-test-index-signed-error"},
		{"examples/programs/index_int_constraint_error", "/tmp/brolang-test-index-int-constraint-error"},
		{"examples/programs/scalar_cast_error", "/tmp/brolang-test-scalar-cast-error"},
		{"examples/programs/array_const_size_error", "/tmp/brolang-test-array-const-size-error"},
	}
	for test_case in cases {
		status := compiler_core.compile_package(test_case.directory, test_case.output)
		testing.expect_value(t, status, 1)
		_ = os.remove(test_case.output)
	}
}

@(test)
function_literals_lower_as_function_pointer_values :: proc(t: ^testing.T) {
	text := `Callbacks :: struct {
	call @func(value i32) i32
	value i32
}
run func(callbacks Callbacks) i32 {
	return callbacks.call(callbacks.value)
}
main func() i32 {
	callbacks Callbacks = Callbacks {
		call = func(value i32) i32 {
			return value + 1
		},
		value = 41,
	}
	return run(callbacks) - 42
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)

	generated_functions := 0
	literal_exprs := 0
	for function in ast_module.functions {
		generated_functions += 1 if function.generated else 0
	}
	for expr in ast_module.exprs {
		literal_exprs += 1 if expr.kind == .Function_Literal else 0
	}
	indirect_calls := 0
	for expr in hir_module.exprs {
		if expr.kind == .Call && expr.left != hir.INVALID_EXPR {
			indirect_calls += 1
		}
	}
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, generated_functions, 1)
	testing.expect_value(t, literal_exprs, 1)
	testing.expect(t, len(ir_module.functions) > 0)
	testing.expect(t, indirect_calls > 0)
}

@(test)
qualified_value_calls_do_not_imply_package_resolution :: proc(t: ^testing.T) {
	text := `Callbacks :: struct {
	call @func() void
}
main func() void {
	callbacks Callbacks = Callbacks{call = func() void {}}
	callbacks.call()
	missing.call()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 1)
	testing.expect_value(t, diagnostics.items[0].message, "unknown symbol 'missing'")
	testing.expect(t, !strings.contains(diagnostics.items[0].message, "package"))
}

@(test)
function_literals_do_not_capture_locals :: proc(t: ^testing.T) {
	text := `main func() i32 {
	offset i32 = 1
	callback @func(value i32) i32 = func(value i32) i32 {
		return value + offset
	}
	return callback(1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "unknown symbol 'offset'")
	}
	testing.expect(t, found)
}

@(test)
field_function_pointer_calls_reject_non_callable_fields :: proc(t: ^testing.T) {
	text := `Box :: struct {
	value i32
}
main func() void {
	box Box = Box { value = 1 }
	box.value()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "call target is not a function pointer")
	}
	testing.expect(t, found)
}

@(test)
allocator_contract_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-mem-allocator"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/mem_allocator", output, nil, target.DEFAULT, cimport.Options{}, ".")
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
allocator_contract_c_allocator_global_lowers :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	ast_module, loaded := loader.load("examples/programs/mem_allocator", &sources, &diagnostics, &symbols, context.allocator, context.allocator, cimport.Options{}, target.DEFAULT, ".")
	defer ast.destroy_module(&ast_module)
	testing.expect(t, loaded)

	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)

	found_c_allocator := false
	found_anyopaque_context := false
	found_vtable_pointer := false
	found_alloc_callback := false
	found_realloc_callback := false
	found_free_callback := false
	for global in hir_module.globals {
		if symbol.resolve(&symbols, global.name) != "c_allocator" {
			continue
		}
		found_c_allocator = true
		for field in types.fields_for(&hir_module.types, global.type) {
			name := symbol.resolve(&symbols, symbol.Id(field.name))
			if name == "context" {
				optional_item, optional_ok := types.node(&hir_module.types, field.type)
				if optional_ok && optional_item.kind == .Optional {
					pointer_item, pointer_ok := types.node(&hir_module.types, optional_item.child)
					found_anyopaque_context = pointer_ok &&
					                           pointer_item.kind == .Pointer &&
					                           pointer_item.mutable &&
					                           !pointer_item.many &&
					                           pointer_item.child == types.ANYOPAQUE
				}
			} else if name == "vtable" {
				pointer_item, pointer_ok := types.node(&hir_module.types, field.type)
				found_vtable_pointer = pointer_ok && pointer_item.kind == .Pointer && !pointer_item.mutable && !pointer_item.many
				if found_vtable_pointer {
					for callback in types.fields_for(&hir_module.types, pointer_item.child) {
						callback_name := symbol.resolve(&symbols, symbol.Id(callback.name))
						callback_pointer, _, _, callable := types.function_pointer(callback.type, &hir_module.types)
						found_alloc_callback = found_alloc_callback || callback_name == "alloc" && callable && !callback_pointer.many
						found_realloc_callback = found_realloc_callback || callback_name == "realloc" && callable && !callback_pointer.many
						found_free_callback = found_free_callback || callback_name == "free" && callable && !callback_pointer.many
					}
				}
			}
		}
	}

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, len(ir_module.functions) > 0)
	testing.expect(t, found_c_allocator)
	testing.expect(t, found_anyopaque_context)
	testing.expect(t, found_vtable_pointer)
	testing.expect(t, found_alloc_callback)
	testing.expect(t, found_realloc_callback)
	testing.expect(t, found_free_callback)
}

@(test)
milestone_25_c_allocator_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-c-allocator"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/mem_allocator", output, nil, target.DEFAULT, cimport.Options{}, ".")
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
milestone_25_c_allocator_emits_libc_alloc_declarations :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	ast_module, loaded := loader.load("examples/programs/mem_allocator", &sources, &diagnostics, &symbols, context.allocator, context.allocator, cimport.Options{}, target.DEFAULT, ".")
	defer ast.destroy_module(&ast_module)
	testing.expect(t, loaded)

	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "declare ptr @malloc(i64)"))
	testing.expect(t, strings.contains(llvm_text, "declare ptr @realloc(ptr, i64)"))
	testing.expect(t, strings.contains(llvm_text, "declare i32 @posix_memalign(ptr, i64, i64)"))
	testing.expect(t, strings.contains(llvm_text, "declare void @free(ptr)"))
}

@(test)
control_flow_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-control-flow"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/control_flow", output)
	testing.expect_value(t, status, 0)
	state, stdout, stderr, _ := os2.process_exec(
		os2.Process_Desc{command=[]string{output}},
		context.allocator,
	)
	defer delete(stdout)
	defer delete(stderr)
	// if / else if / else, comparisons, logical and/or/not, bool locals, and
	// block scoping together produce 42.
	testing.expect_value(t, state.exit_code, 42)
	// Short-circuit: `noisy()` is never reached, so its output must be absent,
	// while the taken or-branch must print.
	testing.expect(t, !strings.contains(string(stdout), "rhs-evaluated"))
	testing.expect(t, strings.contains(string(stdout), "or-taken"))
}

@(test)
break_and_continue_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-break-continue"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/break_continue", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	// `while` break, range-for `continue`, nested innermost-targeting break, a
	// `continue` on the final element of an inclusive `u8` range (no overflow
	// trap), and an exitable `while true` together produce 42.
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
break_and_continue_misuse_is_diagnosed :: proc(t: ^testing.T) {
	// `break`/`continue` outside any loop are rejected, and a non-void function
	// that exits a `while true` via `break` without returning is flagged as
	// missing a return (the `all_paths_return` refinement).
	text := `main func() i32 {
	bad_break()
	bad_continue()
	return missing_return()
}
bad_break func() void {
	break
}
bad_continue func() void {
	continue
}
missing_return func() i32 {
	while true {
		break
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	break_outside := false
	continue_outside := false
	missing := false
	for diagnostic in diagnostics.items {
		break_outside = break_outside || strings.contains(diagnostic.message, "'break' outside of a loop")
		continue_outside = continue_outside || strings.contains(diagnostic.message, "'continue' outside of a loop")
		missing = missing || strings.contains(diagnostic.message, "'missing_return' does not return a value")
	}
	testing.expect(t, break_outside)
	testing.expect(t, continue_outside)
	testing.expect(t, missing)
}

@(test)
defer_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-defer"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/defer", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	// LIFO, runs on fall-through / break / continue / return (with the return value
	// captured before defers run), scoped bare blocks, and `defer { ... }` blocks
	// together produce 42.
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
defer_misuse_is_diagnosed :: proc(t: ^testing.T) {
	// Deferring control flow that would escape the defer is rejected: `defer return`,
	// `defer break`, and a `return` inside a `defer { ... }` block.
	text := `main func() i32 {
	bad_defer_return()
	bad_defer_break()
	bad_return_in_defer()
	bad_errdefer_nonfallible()
	_ = bad_try_in_defer() catch 0
	_ = bad_try_in_errdefer() catch 0
	return 0
}
Failure :: enum { bad }
fail func() i32 ! Failure { return .bad }
bad_defer_return func() void {
	defer return
}
bad_defer_break func() void {
	for 0..3 |i| {
		defer break
		_ = i
	}
}
bad_return_in_defer func() void {
	defer {
		return
	}
}
bad_errdefer_nonfallible func() void {
	errdefer {}
}
bad_try_in_defer func() i32 ! Failure {
	defer _ = try fail()
	return 1
}
bad_try_in_errdefer func() i32 ! Failure {
	errdefer _ = try fail()
	return 1
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	defer_return := false
	defer_break := false
	return_in_defer := false
	errdefer_nonfallible := false
	try_in_defer := 0
	for diagnostic in diagnostics.items {
		defer_return = defer_return || strings.contains(diagnostic.message, "cannot defer a 'return' statement")
		defer_break = defer_break || strings.contains(diagnostic.message, "cannot defer a 'break' statement")
		return_in_defer = return_in_defer || strings.contains(diagnostic.message, "cannot 'return' inside a 'defer'")
		errdefer_nonfallible = errdefer_nonfallible || strings.contains(diagnostic.message, "'errdefer' requires an enclosing fallible function")
		try_in_defer += 1 if strings.contains(diagnostic.message, "cannot 'try' inside a 'defer'") else 0
	}
	testing.expect(t, defer_return)
	testing.expect(t, defer_break)
	testing.expect(t, return_in_defer)
	testing.expect(t, errdefer_nonfallible)
	testing.expect_value(t, try_in_defer, 2)
}

@(test)
errdefer_capture_syntax_is_diagnosed :: proc(t: ^testing.T) {
	text := `Failure :: enum { bad }
bad func() i32 ! Failure {
	errdefer || {}
	errdefer |first, second| {}
	return .bad
}
main func() i32 { return bad() catch 0 }
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	missing := false
	multiple := false
	for diagnostic in diagnostics.items {
		missing = missing || strings.contains(diagnostic.message, "expected an errdefer capture name")
		multiple = multiple || strings.contains(diagnostic.message, "'errdefer' accepts exactly one capture")
	}
	testing.expect(t, missing)
	testing.expect(t, multiple)
}

@(test)
yield_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-yield"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/yield", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	// Value blocks, value if-statements (incl. `return` branches and unwrap-`if`),
	// `orelse`, value loops, labeled value blocks (`blk: { … yield :blk v }`, incl.
	// defer-capture, `{T,none}` → optional, and `none` before a concrete yield that uses a
	// block local), outer-loop control (`yield :outer v` / `break :outer`), and labeled
	// block statements exited via `break :blk` together produce 42.
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
value_loop_label_does_not_shadow_own_yield_target :: proc(t: ^testing.T) {
	text := `main func() i32 {
	idx :: for 0..10 |i| hit: {
		if (i == 3) yield :hit i
		yield none
	}
	if idx |found| {
		if (found == 3) return 0
		return 1
	}
	return 2
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
native_union_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-unions"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/unions", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	// A native untagged union (`Val :: union { n i32, f f64 }`) constructed via a keyed
	// literal, stored into a local, and read back through field access reinterprets the
	// carrier and yields 42 (declaration → construct → store → load → field read).
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
tagged_union_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-tagged-union"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/tagged_union", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	// Both tagged forms — `union(Animal)` (existing enum tag) and `union(enum)` (synthesized
	// tag) — constructed via keyed literals, stored as `{tag, payload}`, with the active
	// payload read back at its post-tag offset: 37 + 5 = 42. Non-zero payloads make a wrong
	// payload offset (e.g. overlapping the tag) fail the exit code.
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
tagged_union_stores_the_discriminant :: proc(t: ^testing.T) {
	// The runtime test observes only the payload; this one checks the *tag* is written.
	// Native sum tags are global u16 IDs. `Animal` contributes dog/cat/bird (1..3),
	// then `Data` contributes dog:i32/bird:i32 (4..5), so `Data{ bird = 99 }`
	// writes discriminant `store i16 5` beside the payload.
	text := `Animal :: enum {
	dog
	cat
	bird
}
Data :: union(Animal) {
	dog  i32
	bird i32
}
main func() i32 {
	x Data = Data{ bird = 99 }
	return x.bird
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "{ i16, [2 x i8], i32 }"))
	testing.expect(t, strings.contains(llvm_text, "store i16 5,"))
	testing.expect(t, strings.contains(llvm_text, "store i32 99,"))
}

@(test)
tagged_union_validation_is_diagnosed :: proc(t: ^testing.T) {
	// A `union(T)` tag must be an enum, and every variant of a `union(Enum)` must name a
	// member of that enum.
	text := `Color :: struct {
	r u8
}
Animal :: enum {
	dog
	cat
}
BadTag :: union(Color) {
	dog i32
}
BadVariant :: union(Animal) {
	snake i32
}
main func() i32 {
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_tag := false
	found_variant := false
	for diagnostic in diagnostics.items {
		found_tag = found_tag || strings.contains(diagnostic.message, "tagged union's tag must be an enum")
		found_variant = found_variant || strings.contains(diagnostic.message, "'snake' is not a member of the tag enum")
	}
	testing.expect(t, found_tag)
	testing.expect(t, found_variant)
}

@(test)
sum_composition_merges_widens_and_rejects_conflicts :: proc(t: ^testing.T) {
	text := `A :: enum {
	same
	left
}
B :: enum {
	same
	right
}
Both :: alias A | B
UA :: union(enum) {
	item i32
}
UB :: union(enum) {
	empty void
}
UBoth :: alias UA | UB
pick func(value Both) i32 {
	match value {
		.same:  return 1
		.left:  return 2
		.right: return 3
	}
}
payload func(value UBoth) i32 {
	match value {
		.item |n|: return n
		.empty:   return 5
	}
}
main func() i32 {
	a A = .left
	b B = .right
	u UA = UA{ item = 4 }
	v UB = .empty
	return pick(.same) + pick(a) + pick(b) + payload(u) + payload(v)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "call void @llvm.memcpy.p0.p0.i64"))

	conflict := `A :: union(enum) {
	dup i32
}
B :: union(enum) {
	dup i64
}
Bad :: alias A | B
main func() void {}
`
	conflict_source := source.Source{path="conflict.bro", text=conflict}
	conflict_diagnostics := source.init_diagnostics(&conflict_source)
	defer source.destroy_diagnostics(&conflict_diagnostics)
	conflict_symbols := symbol.init_table()
	defer symbol.destroy_table(&conflict_symbols)
	conflict_stream := lexer.lex(&conflict_source, &conflict_diagnostics, &conflict_symbols)
	defer delete(conflict_stream.items)
	conflict_module := parser.parse(&conflict_stream, &conflict_source, &conflict_diagnostics)
	defer ast.destroy_module(&conflict_module)
	found_conflict := false
	for diagnostic in conflict_diagnostics.items {
		found_conflict = found_conflict || strings.contains(diagnostic.message, "same variant name")
	}
	testing.expect(t, found_conflict)

	backed := `A :: enum(u8) {
	a = 1
}
B :: enum {
	b
}
Bad :: alias A | B
main func() void {}
`
	backed_source := source.Source{path="backed.bro", text=backed}
	backed_diagnostics := source.init_diagnostics(&backed_source)
	defer source.destroy_diagnostics(&backed_diagnostics)
	backed_symbols := symbol.init_table()
	defer symbol.destroy_table(&backed_symbols)
	backed_stream := lexer.lex(&backed_source, &backed_diagnostics, &backed_symbols)
	defer delete(backed_stream.items)
	backed_module := parser.parse(&backed_stream, &backed_source, &backed_diagnostics)
	defer ast.destroy_module(&backed_module)
	found_backed := false
	for diagnostic in backed_diagnostics.items {
		found_backed = found_backed || strings.contains(diagnostic.message, "native unbacked")
	}
	testing.expect(t, found_backed)
}

@(test)
yield_inference_visits_yielded_calls :: proc(t: ^testing.T) {
	text := `identity func(value int) int {
	return value
}
main func() i32 {
	value :: {
		yield identity(41)
	}
	return value - 41
}
`
	source_file := source.Source{path="yield_call.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, len(hir_module.functions) > 1)
}

@(test)
fallible_ergonomics_rejects_bad_try_and_catch_blocks :: proc(t: ^testing.T) {
	text := `A :: enum {
	a
}
B :: enum {
	b
}
fa func() i32 ! A {
	return .a
}
bad_error func() i32 ! B {
	x :: try fa()
	return x
}
bad_catch func() i32 {
	return fa() catch |e| {
		_ = e
	}
}
bad_nested_match func() i32 {
	return fa() catch |e| {
		match e {
			.a: yield 3
		}
	}
}
main func() i32 {
	_ = bad_error() catch 0
	return bad_catch() + bad_nested_match()
}
`
	source_file := source.Source{path="fallible_ergonomics.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_error := false
	found_yield := false
	found_misplaced_yield := false
	for diagnostic in diagnostics.items {
		found_error = found_error || strings.contains(diagnostic.message, "'try' error channel cannot be widened")
		found_yield = found_yield || strings.contains(diagnostic.message, "a value block must end with an explicit 'yield'")
		found_misplaced_yield = found_misplaced_yield || strings.contains(diagnostic.message, "'yield' is only valid as the final statement")
	}
	testing.expect(t, found_error)
	testing.expect(t, found_yield)
	testing.expect(t, found_misplaced_yield)

	success_text := `A :: enum {
	a
}
B :: enum {
	b
}
Both :: alias A | B
fs func() i64 ! A {
	return 1
}
bad_success func() i32 ! Both {
	x :: try fs()
	return x
}
main func() i32 {
	return bad_success() catch 0
}
`
	directory := "/tmp/brolang-test-try-success-mismatch"
	main_path := "/tmp/brolang-test-try-success-mismatch/main.bro"
	output := "/tmp/brolang-test-try-success-mismatch-output"
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)success_text))
	testing.expect_value(t, compiler_core.compile_package(directory, output), 1)
}

@(test)
terminating_catch_block_compiles_and_runs :: proc(t: ^testing.T) {
	text := `Failure :: enum {
	bad
}
may_fail func(fail bool) i32 ! Failure {
	if (fail) return .bad
	return 1
}
recover func(fail bool) i32 {
	value :: may_fail(fail) catch |_| {
		return 40
	}
	return value + 1
}
main func() i32 {
	return recover(false) + recover(true) - 42
}
`
	directory := "/tmp/brolang-test-terminating-catch"
	main_path := "/tmp/brolang-test-terminating-catch/main.bro"
	output := "/tmp/brolang-test-terminating-catch-output"
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	testing.expect_value(t, compiler_core.compile_package(directory, output), 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
fallible_void_fallthrough_compiles_at_runtime_and_comptime :: proc(t: ^testing.T) {
	text := `Failure :: enum {
	bad
}
succeed func() void ! Failure {}
fail func() void ! Failure { return .bad }
maybe func(should_fail bool) void ! Failure {
	if should_fail { return .bad }
}
recover func(exit bool) i32 {
	fail() catch |_| {
		if exit { return 7 }
	}
	return 0
}
comptime_scenario func() i32 {
	succeed() catch |_| {}
	fail() catch |_| {}
	return 0
}
main func() i32 {
	comptime_result i32 :: $comptime_scenario()
	handled bool = false
	fail() catch |_| { handled = true }
	if !handled { return 3 }
	succeed() catch |_| { return 1 }
	maybe(false) catch |_| { return 2 }
	return comptime_result + recover(false) + recover(true) - 7
}
`
	directory := "/tmp/brolang-test-fallible-void-fallthrough"
	main_path := "/tmp/brolang-test-fallible-void-fallthrough/main.bro"
	output := "/tmp/brolang-test-fallible-void-fallthrough-output"
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	testing.expect_value(t, compiler_core.compile_package(directory, output), 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
conversion_diagnostics_render_source_types :: proc(t: ^testing.T) {
	text := `Allocator :: struct {
	marker i32
}
take func(allocator Allocator, memory []mut u8) void {}
main func() void {
	allocator Allocator = Allocator { marker = 0 }
	data [1]mut u8 = [0]
	take(data[..], allocator)
}
`
	source_file := source.Source{path="type_labels.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	slice_to_allocator := false
	allocator_to_slice := false
	internal_type_id := false
	for diagnostic in diagnostics.items {
		slice_to_allocator = slice_to_allocator ||
			strings.contains(diagnostic.message, "cannot implicitly convert []mut u8 to Allocator")
		allocator_to_slice = allocator_to_slice ||
			strings.contains(diagnostic.message, "cannot implicitly convert Allocator to []mut u8")
		internal_type_id = internal_type_id || strings.contains(diagnostic.message, "<type ")
	}
	testing.expect(t, slice_to_allocator)
	testing.expect(t, allocator_to_slice)
	testing.expect(t, !internal_type_id)
}

@(test)
contextual_payload_variants_compile :: proc(t: ^testing.T) {
	text := `DetailError :: union(enum) {
	code i32
	empty void
}
make_payload func() i32 {
	return 7
}
accept func(value DetailError) i32 {
	match value {
		.code |n|: return n
		.empty:    return 0
	}
}
make_code func(value i32) DetailError {
	return .code{value}
}
with_detail func(value i32) i32 ! DetailError {
	if (value == 0) return .code{5}
	if (value == 1) return .empty
	return value
}
main func() i32 {
	e DetailError = .code{3}
	recovered :: with_detail(0) catch |err| {
		result i32 :: match err {
			.code |n|: n
			.empty:    9
		}
		yield result
	}
	return accept(e) + accept(.code{4}) + accept(make_code(5)) + accept(.code{make_payload()}) + recovered - 24
}
`
	source_file := source.Source{path="contextual_payload.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "call void @llvm.memcpy.p0.p0.i64"))
}

@(test)
anonymous_struct_payloads_and_keyed_payload_sugar_compile :: proc(t: ^testing.T) {
	text := `PayloadError :: union(enum) {
	not_found struct {
		path i32
		line i32
	}
	wrapped struct {
		path i32
		line i32
	}
	scalar i32
	empty void
}
OtherError :: union(enum) {
	not_found struct {
		path i32
		line i32
	}
	other void
}
BothError :: alias PayloadError | OtherError
accept func(value PayloadError) i32 {
	match value {
		.not_found |info|: return info.path + info.line
		.wrapped |info|:   return info.path * 10 + info.line
		.scalar |n|:       return n
		.empty:            return 0
	}
}
with_payload func(value i32) i32 ! PayloadError {
	if (value == 0) return .not_found{path = 4, line = 5}
	if (value == 1) return .scalar{7}
	return value
}
inline_payload func(value i32) i32 ! union(enum) {
	inline_bad struct {
		code i32
		line i32
	}
} {
	if (value == 0) return .inline_bad{code = 6, line = 7}
	return value
}
main func() i32 {
	e PayloadError = .not_found{path = 1, line = 2}
	a :: accept(e)
	b :: accept(.wrapped{line = 4, path = 3})
	c :: with_payload(0) catch |err| {
		result i32 :: match err {
			.not_found |info|: info.path + info.line
			.wrapped |info|:   info.path + info.line
			.scalar |n|:       n
			.empty:            0
		}
		yield result
	}
	d :: inline_payload(0) catch |err| {
		result i32 :: match err {
			.inline_bad |info|: info.code + info.line
		}
		yield result
	}
	return a + b + c + d - 59
}
`
	source_file := source.Source{path="anonymous_payloads.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, len(llvm_text) > 0)
}

@(test)
inline_fallible_error_types_compile :: proc(t: ^testing.T) {
	text := `inline_enum func(value i32) i32 ! enum {
	inline_bad
	inline_worse
} {
	if (value == 0) return .inline_bad
	if (value < 0) return .inline_worse
	return value
}
inline_union func(value i32) i32 ! union(enum) {
	inline_code i32
	inline_empty void
} {
	if (value == 0) return .inline_code{6}
	if (value == 1) return .inline_empty
	return value
}
main func() i32 {
	a :: inline_enum(0) catch |e| {
		result i32 :: if (e == .inline_bad) {
			yield 10
		} else {
			yield 11
		}
		yield result
	}
	b :: inline_union(0) catch |e| {
		result i32 :: match e {
			.inline_code |n|: n
			.inline_empty:   12
		}
		yield result
	}
	return a + b - 16
}
`
	source_file := source.Source{path="expand_errors.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, len(hir_module.functions) > 1)
	testing.expect(t, len(llvm_text) > 0)
}

@(test)
contextual_payload_variants_reject_bad_forms :: proc(t: ^testing.T) {
	text := `DetailError :: union(enum) {
	code i32
	empty void
}
missing_payload func() DetailError {
	return .code
}
void_payload func() DetailError {
	return .empty{1}
}
empty_payload func() DetailError {
	return .code{}
}
multi_payload func() DetailError {
	return .code{1, 2}
}
unknown_payload func() DetailError {
	return .missing{1}
}
no_context func() i32 {
	_ = .code{1}
	return 0
}
main func() i32 {
	_ = missing_payload()
	_ = void_payload()
	_ = empty_payload()
	_ = multi_payload()
	_ = unknown_payload()
	return no_context()
}
`
	source_file := source.Source{path="bad_contextual_payload.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_missing := false
	found_void := false
	payload_arity_errors := 0
	found_unknown := false
	found_no_context := false
	for diagnostic in diagnostics.items {
		found_missing = found_missing || strings.contains(diagnostic.message, "needs a payload")
		found_void = found_void || strings.contains(diagnostic.message, "void variant 'empty' takes no value")
		payload_arity_errors += 1 if strings.contains(diagnostic.message, "requires exactly one expression") else 0
		found_unknown = found_unknown || strings.contains(diagnostic.message, "unknown variant '.missing'")
		found_no_context = found_no_context || strings.contains(diagnostic.message, "requires a tagged-union context")
	}
	testing.expect(t, found_missing)
	testing.expect(t, found_void)
	testing.expect(t, payload_arity_errors >= 2)
	testing.expect(t, found_unknown)
	testing.expect(t, found_no_context)
}

@(test)
anonymous_struct_payloads_reject_bad_forms :: proc(t: ^testing.T) {
	text := `Bad :: union(enum) {
	payload struct {
		x i32
		y i32
	}
	scalar i32
}
unknown func() Bad {
	return .payload{x = 1, z = 2}
}
duplicate func() Bad {
	return .payload{x = 1, x = 2, y = 3}
}
missing func() Bad {
	return .payload{x = 1}
}
scalar_keyed func() Bad {
	return .scalar{value = 1}
}
A :: union(enum) {
	dup struct {
		x i32
	}
}
B :: union(enum) {
	dup struct {
		x i64
	}
}
Conflict :: alias A | B
main func() i32 {
	_ = unknown()
	_ = duplicate()
	_ = missing()
	_ = scalar_keyed()
	return 0
}
`
	source_file := source.Source{path="bad_anonymous_payloads.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_unknown := false
	found_duplicate := false
	found_missing := false
	found_keyed_non_struct := false
	found_conflict := false
	for diagnostic in diagnostics.items {
		found_unknown = found_unknown || strings.contains(diagnostic.message, "unknown struct field 'z'")
		found_duplicate = found_duplicate || strings.contains(diagnostic.message, "duplicate initializer for struct field 'x'")
		found_missing = found_missing || strings.contains(diagnostic.message, "missing initializer for struct field 'y'")
		found_keyed_non_struct = found_keyed_non_struct || strings.contains(diagnostic.message, "keyed contextual payload requires a struct payload")
		found_conflict = found_conflict || strings.contains(diagnostic.message, "same variant name")
	}
	testing.expect(t, found_unknown)
	testing.expect(t, found_duplicate)
	testing.expect(t, found_missing)
	testing.expect(t, found_keyed_non_struct)
	testing.expect(t, found_conflict)
}

@(test)
errors_example_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-errors"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/errors", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
match_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-match"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/match", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	// Exercises every match form — tagged-union statement match with payload capture,
	// tagged-union value match (implicit + explicit yield), enum statement/value match,
	// and integer match with `else` — all summed to a self-checking 0 on success.
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
match_dispatches_on_the_tag :: proc(t: ^testing.T) {
	// A tagged-union match desugars to: read the discriminant once (a load of the tag
	// enum at the union's offset 0), then compare it against each variant's tag value.
	// Data's runtime tag is the hidden global u16 variant ID.
	text := `Animal :: enum {
	dog
	cat
	bird
}
Data :: union(Animal) {
	dog  i32
	bird i32
}
main func() i32 {
	d Data = Data{ bird = 7 }
	out i32 = 0
	match d {
		.dog |v|: out = v
		.bird |v|: out = v + 1
	}
	return out
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "load i16"))
	testing.expect(t, strings.contains(llvm_text, "icmp eq i16"))
}

@(test)
match_misuse_is_diagnosed :: proc(t: ^testing.T) {
	// Five rejected matches: (1) a non-exhaustive enum match with no `else`, (2) a scalar
	// match missing its mandatory `else`, (3) a payload capture on a non-union arm, (4) a
	// redundant `else` on an already-exhaustive match, and (5) an unknown variant.
	text := `Animal :: enum {
	dog
	cat
	bird
}
Data :: union(Animal) {
	dog  i32
	bird i32
}
not_exhaustive func(a Animal) i32 {
	match a {
		.dog: { return 1 }
		.cat: { return 2 }
	}
	return 0
}
missing_else func(n i32) i32 {
	match n {
		0: { return 1 }
		1: { return 2 }
	}
	return 0
}
bad_capture func(a Animal) i32 {
	match a {
		.dog |v|: { return 1 }
		.cat: { return 2 }
		.bird: { return 3 }
	}
	return 0
}
redundant_else func(a Animal) i32 {
	match a {
		.dog: { return 1 }
		.cat: { return 2 }
		.bird: { return 3 }
		else: { return 4 }
	}
	return 0
}
unknown_variant func(d Data) i32 {
	match d {
		.dog: { return 1 }
		.snake: { return 2 }
		else: { return 3 }
	}
	return 0
}
main func() i32 {
	# Functions are specialized on use, so call each so its body is type-checked.
	d Data = Data{ dog = 0 }
	return not_exhaustive(.dog) + missing_else(0) + bad_capture(.dog) +
		redundant_else(.dog) + unknown_variant(d)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_exhaustive := false
	found_missing_else := false
	found_capture := false
	found_redundant := false
	found_unknown := false
	for diagnostic in diagnostics.items {
		found_exhaustive = found_exhaustive || strings.contains(diagnostic.message, "is not exhaustive")
		found_missing_else = found_missing_else || strings.contains(diagnostic.message, "requires an 'else' arm")
		found_capture = found_capture || strings.contains(diagnostic.message, "only tagged-union variants can capture")
		found_redundant = found_redundant || strings.contains(diagnostic.message, "redundant 'else'")
		found_unknown = found_unknown || strings.contains(diagnostic.message, "unknown variant '.snake'")
	}
	testing.expect(t, found_exhaustive)
	testing.expect(t, found_missing_else)
	testing.expect(t, found_capture)
	testing.expect(t, found_redundant)
	testing.expect(t, found_unknown)
}

@(test)
match_range_arm_emits_bounds :: proc(t: ^testing.T) {
	// A scalar range arm `lo..hi:` desugars to `key >= lo and key < hi` (inclusive uses
	// `<=`), emitted as signed integer comparisons for an i32 subject.
	text := `main func() i32 {
	n i32 = 5
	out i32 = 0
	match n {
		0..10:   out = 1
		10..=20: out = 2
		else:    out = 3
	}
	return out
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "icmp sge i32")) // key >= lo
	testing.expect(t, strings.contains(llvm_text, "icmp slt i32")) // key < hi (exclusive)
	testing.expect(t, strings.contains(llvm_text, "icmp sle i32")) // key <= hi (inclusive)
}

@(test)
match_extended_misuse_is_diagnosed :: proc(t: ^testing.T) {
	// Five rejected forms from milestone 22.5: (1) a capture on a void variant, (2) a value
	// given to a void variant in construction, (3) a bare key on a non-void field, (4) a
	// range pattern on an enum subject, and (5) a multi-pattern capture whose variants have
	// different payload types. (Pointer capture on an rvalue subject is also rejected, but
	// match-on-call-result is a separate pre-existing gap so it isn't exercised here.)
	text := `Animal :: enum {
	dog
	cat
	bird
}
Point :: struct {
	x i32
	y i32
}
Box :: union(enum) {
	point Point
	count i32
	empty void
}
void_capture func(b Box) i32 {
	match b {
		.point |p|: { return p.x }
		.count |c|: { return c }
		.empty |x|: { return 0 }
	}
	return 0
}
void_value func() i32 {
	b Box = Box{ empty = 5 }
	return 0
}
bare_on_nonvoid func() i32 {
	b Box = Box{ count }
	return 0
}
range_on_enum func(a Animal) i32 {
	match a {
		0..2: { return 1 }
		else: { return 0 }
	}
	return 0
}
incompatible_capture func(b Box) i32 {
	match b {
		.point, .count |v|: { return 0 }
		.empty: { return 0 }
	}
	return 0
}
main func() i32 {
	b Box = Box{ count = 1 }
	return void_capture(b) + void_value() + bare_on_nonvoid() + range_on_enum(.dog) +
		incompatible_capture(b)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_void_capture := false
	found_void_value := false
	found_bare := false
	found_range_enum := false
	found_incompatible := false
	for diagnostic in diagnostics.items {
		found_void_capture = found_void_capture || strings.contains(diagnostic.message, "void payload")
		found_void_value = found_void_value || strings.contains(diagnostic.message, "void variant 'empty' takes no value")
		found_bare = found_bare || strings.contains(diagnostic.message, "field 'count' requires a value")
		found_range_enum = found_range_enum || strings.contains(diagnostic.message, "range patterns only apply to scalar")
		found_incompatible = found_incompatible || strings.contains(diagnostic.message, "capture group with incompatible types")
	}
	testing.expect(t, found_void_capture)
	testing.expect(t, found_void_value)
	testing.expect(t, found_bare)
	testing.expect(t, found_range_enum)
	testing.expect(t, found_incompatible)
}

@(test)
match_call_subject_and_contextual_void_compile :: proc(t: ^testing.T) {
	// Milestone 22.6: (1) a call expression directly as the match subject (`match get()`)
	// now specializes — previously "could not resolve specialization of 'get'" — because the
	// inference pass visits the match subject; (2) a void variant constructed contextually
	// (`e Box = .empty`) coerces the bare enum literal to the union. Both compile clean to IR.
	text := `Animal :: enum {
	dog
	cat
	bird
}
Box :: union(enum) {
	count i32
	empty void
}
get func() Animal {
	return .bird
}
main func() i32 {
	e Box = .empty
	r i32 = 0
	match get() {
		.dog:  r = 1
		.cat:  r = 2
		.bird: r = 3
	}
	match e {
		.count |c|: r = r + c
		.empty:     r = r + 7
	}
	return r
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "icmp eq")) // the call subject still dispatches
}

@(test)
match_contextual_payload_variant_is_diagnosed :: proc(t: ^testing.T) {
	// Contextual construction is only for void variants; a bare `.point` for a payload
	// variant must use `Box{ point = ... }` instead.
	text := `Point :: struct {
	x i32
	y i32
}
Box :: union(enum) {
	point Point
	empty void
}
bad func() i32 {
	e Box = .point
	return 0
}
main func() i32 {
	return bad()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "needs a payload")
	}
	testing.expect(t, found)
}

@(test)
yield_misuse_is_diagnosed :: proc(t: ^testing.T) {
	// A value block that does not end in `yield`, and a `yield` nested inside an
	// `if` within a value block (only the final statement may yield).
	text := `main func() i32 {
	missing :: {
		k :: 5
	}
	nested :: {
		if (true) {
			yield 1
		}
		yield 2
	}
	return missing + nested
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	missing_yield := false
	misplaced_yield := false
	for diagnostic in diagnostics.items {
		missing_yield = missing_yield || strings.contains(diagnostic.message, "a value block must end with an explicit 'yield'")
		misplaced_yield = misplaced_yield || strings.contains(diagnostic.message, "'yield' is only valid as the final statement of a value block")
	}
	testing.expect(t, missing_yield)
	testing.expect(t, misplaced_yield)
}

@(test)
yield_control_flow_is_diagnosed :: proc(t: ^testing.T) {
	// Value if/loop/block misuse: an `if` value without an `else`; a branch that neither
	// yields nor exits on every path (20.6); a value loop whose body lacks a trailing
	// fall-through `yield`; a `yield :label` with no matching value loop; a labeled value
	// block that does not yield on every path; a `break :label` naming no loop; and a
	// `continue :label` targeting a block (not a loop).
	text := `main func() i32 {
	noelse :: if (true) {
		yield 1
	}
	badbranch :: if (true) {
		k :: 5
	} else {
		yield 2
	}
	noloopyield :: for 0..10 |i| blk: {
		if (i == 0) yield :blk i
	}
	for 0..10 |j| stray: {
		yield :stray j
	}
	noblockyield :: blk: {
		if (true) yield :blk 1
		k2 :: 5
	}
	for 0..10 |m| {
		break :nope
	}
	scope: {
		continue :scope
	}
	return noelse + badbranch + noloopyield + noblockyield
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	no_else := false
	branch_no_yield := false
	loop_no_yield := false
	stray_label := false
	block_no_yield := false
	bad_break_label := false
	continue_block := false
	for diagnostic in diagnostics.items {
		no_else = no_else || strings.contains(diagnostic.message, "an 'if' used as a value must have an 'else'")
		branch_no_yield = branch_no_yield || strings.contains(diagnostic.message, "a value branch must end with 'yield' or exit on every path")
		loop_no_yield = loop_no_yield || strings.contains(diagnostic.message, "a value loop's body must end with a 'yield'")
		stray_label = stray_label || strings.contains(diagnostic.message, "no enclosing value loop or block is labeled 'stray'")
		block_no_yield = block_no_yield || strings.contains(diagnostic.message, "a labeled value block must 'yield' on every path")
		bad_break_label = bad_break_label || strings.contains(diagnostic.message, "no enclosing loop is labeled 'nope'")
		// `continue :scope` targets a labeled block, which is not a loop.
		continue_block = continue_block || strings.contains(diagnostic.message, "no enclosing loop is labeled 'scope'")
	}
	testing.expect(t, no_else)
	testing.expect(t, branch_no_yield)
	testing.expect(t, loop_no_yield)
	testing.expect(t, stray_label)
	testing.expect(t, block_no_yield)
	testing.expect(t, bad_break_label)
	testing.expect(t, continue_block)
}

@(test)
foreign_function_links_from_c_source :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-foreign-source"
	defer _ = os.remove(output)
	arguments := []linker.Argument{{kind=.Input, value="examples/interop/manual/native.c"}}
	status := compiler_core.compile_package("examples/interop/manual", output, arguments)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
restricted_c_header_imports_compile_and_link :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-header-import"
	defer _ = os.remove(output)
	arguments := []linker.Argument{{kind=.Input, value="examples/interop/header/native.c"}}
	c_options := cimport.Options{
		include_paths=[]string{"examples/interop/header/include"},
		defines=[]string{"BROLANG_FEATURE"},
	}
	status := compiler_core.compile_package("examples/interop/header/app", output, arguments, target.DEFAULT, c_options)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
by_value_c_records_and_unions_compile_and_link :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-records"
	defer _ = os.remove(output)
	arguments := []linker.Argument{{kind=.Input, value="examples/interop/records/native.c"}}
	c_options := cimport.Options{include_paths=[]string{"examples/interop/records/include"}}
	status := compiler_core.compile_package("examples/interop/records/app", output, arguments, target.DEFAULT, c_options)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 1)
}

@(test)
self_referential_c_records_import_and_compile :: proc(t: ^testing.T) {
	// `struct Node { struct Node *next; int value; }`: the importer must not recurse
	// forever populating the self-referential record, and the checker must accept the
	// self-referential `?*mut Node` field as C-layout-compatible.
	output := "/tmp/brolang-test-recursive"
	defer _ = os.remove(output)
	c_options := cimport.Options{include_paths=[]string{"examples/interop/recursive/include"}}
	status := compiler_core.compile_package("examples/interop/recursive/app", output, nil, target.DEFAULT, c_options)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
unsupported_c_header_members_diagnose_only_when_referenced :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-header-unsupported"
	defer _ = os.remove(output)
	c_options := cimport.Options{include_paths=[]string{"examples/interop/header/include"}}
	status := compiler_core.compile_package("examples/interop/header_unsupported", output, nil, target.DEFAULT, c_options)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
compatible_c_header_redeclarations_share_one_llvm_declaration :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-header-duplicate"
	defer _ = os.remove(output)
	arguments := []linker.Argument{{kind=.Input, value="examples/interop/header/native.c"}}
	c_options := cimport.Options{include_paths=[]string{"examples/interop/header/include"}}
	status := compiler_core.compile_package("examples/interop/header_duplicate", output, arguments, target.DEFAULT, c_options)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
interop_foundation_matches_zig_compiled_apple_silicon_c_fixture :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-interop-foundation"
	defer _ = os.remove(output)
	arguments := []linker.Argument{{kind=.Input, value="examples/interop/foundation/native.c"}}
	status := compiler_core.compile_package("examples/interop/foundation", output, arguments)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 1)
}

@(test)
foreign_function_links_from_object :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-foreign-object"
	object := "/tmp/brolang-test-foreign-object.o"
	defer _ = os.remove(output)
	defer _ = os.remove(object)
	testing.expect(t, prepare_native_object(object))
	arguments := []linker.Argument{{kind=.Input, value=object}}
	status := compiler_core.compile_package("examples/interop/manual", output, arguments)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
foreign_function_links_from_direct_library :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-foreign-direct-library"
	object := "/tmp/brolang-test-foreign-direct-library.o"
	archive := "/tmp/brolang-test-foreign-direct-library.a"
	defer _ = os.remove(output)
	defer _ = os.remove(object)
	defer _ = os.remove(archive)
	testing.expect(t, prepare_native_object(object))
	testing.expect(t, prepare_native_archive(object, archive))
	arguments := []linker.Argument{{kind=.Input, value=archive}}
	status := compiler_core.compile_package("examples/interop/manual", output, arguments)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
foreign_function_links_from_named_library :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-foreign-named-library"
	object := "/tmp/brolang-test-foreign-named-library.o"
	archive := "/tmp/libbrolang-test-foreign-named.a"
	defer _ = os.remove(output)
	defer _ = os.remove(object)
	defer _ = os.remove(archive)
	testing.expect(t, prepare_native_object(object))
	testing.expect(t, prepare_native_archive(object, archive))
	arguments := []linker.Argument{
		{kind=.Library_Path, value="/tmp"},
		{kind=.Library, value="brolang-test-foreign-named"},
	}
	status := compiler_core.compile_package("examples/interop/manual", output, arguments)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
one_line_main_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-one-line-main"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/one_line", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 7)
}

@(test)
folded_constant_addition_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-constant-fold"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/constant_fold", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
main_int_is_constrained_to_i32 :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-main-int"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/main_int", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 3)
}

@(test)
main_i32_returns_directly :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-main-i32"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/main_i32", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 4)
}

@(test)
checked_addition_traps_on_overflow :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-overflow"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/overflow", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
checked_runtime_negation_traps_for_every_signed_width :: proc(t: ^testing.T) {
	Case :: struct {
		type_name: string,
		magnitude: string,
	}
	cases := [?]Case{
		{type_name="i8", magnitude="128"},
		{type_name="i16", magnitude="32768"},
		{type_name="i32", magnitude="2147483648"},
		{type_name="i64", magnitude="9223372036854775808"},
	}
	for test_case in cases {
		directory := fmt.aprintf("/tmp/brolang-test-negate-overflow-%s", test_case.type_name)
		main_path := fmt.aprintf("%s/main.bro", directory)
		output := fmt.aprintf("/tmp/brolang-test-negate-overflow-output-%s", test_case.type_name)
		builder := strings.builder_make()
		fmt.sbprintf(
			&builder,
			"negate func(value %s) %s {{ return -value }}\nmain func() void {{ _ = negate(-%s) }}\n",
			test_case.type_name,
			test_case.type_name,
			test_case.magnitude,
		)
		text := strings.clone(strings.to_string(builder))
		strings.builder_destroy(&builder)
		_ = os2.remove_all(directory)
		_ = os.remove(output)
		testing.expect(t, os.make_directory(directory) == nil)
		testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
		status := compiler_core.compile_package(directory, output)
		testing.expect_value(t, status, 0)
		state := run_executable(output)
		testing.expect(t, !state.success)
		_ = os.remove(output)
		_ = os2.remove_all(directory)
		delete(text)
		delete(output)
		delete(main_path)
		delete(directory)
	}
}

@(test)
constant_that_does_not_fit_context_produces_trap_executable :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-constant-context-error"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/constant_context_error", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
constant_beyond_i64_produces_trap_executable :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-constant-i64-overflow"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/constant_i64_overflow", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
same_line_statements_are_diagnosed :: proc(t: ^testing.T) {
	text := "main func() void { _ = 1 _ = 2 }\n"
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)
	testing.expect(t, len(diagnostics.items) > 0)
}

@(test)
missing_main_produces_trap_executable :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-missing-main"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/missing_main", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
backend_failure_preserves_existing_output :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-preserved-output"
	defer _ = os.remove(output)
	previous := "previous artifact"
	testing.expect(t, os.write_entire_file(output, transmute([]byte)previous))
	testing.expect(t, !backend.compile("/definitely/not/llvm.ll", output))
	data, ok := os.read_entire_file(output)
	defer delete(data)
	testing.expect(t, ok)
	testing.expect_value(t, string(data), previous)
}

@(test)
backend_translates_link_arguments_without_reordering_them :: proc(t: ^testing.T) {
	arguments := []linker.Argument{
		{kind=.Input, value="native.c"},
		{kind=.Library_Path, value="vendor/lib"},
		{kind=.Library, value="thing"},
		{kind=.Input, value="helper.o"},
	}
	c_options := cimport.Options{
		include_paths=[]string{"vendor/include"},
		defines=[]string{"FEATURE=1"},
	}
	command := backend.build_command("module.ll", "program", arguments, target.DEFAULT, c_options)
	defer backend.destroy_command(command)

	expected_prefix := []string{
		"/usr/bin/env",
		"zig",
		"cc",
		"-target",
		"aarch64-macos",
		"-Wno-override-module",
		"-Wno-unused-command-line-argument",
	}
	testing.expect(t, len(command) >= len(expected_prefix))
	for value, index in expected_prefix {
		testing.expect_value(t, command[index], value)
	}

	tail_index := len(expected_prefix)
	if sdk, ok := backend.macos_sdk_root(); ok {
		defer delete(sdk)
		frameworks := fmt.tprintf("-F%s/System/Library/Frameworks", sdk)
		lib_dir := fmt.tprintf("-L%s/usr/lib", sdk)
		testing.expect(t, len(command) >= tail_index + 2)
		testing.expect_value(t, command[tail_index], frameworks)
		testing.expect_value(t, command[tail_index + 1], lib_dir)
		tail_index += 2
	}

	expected_tail := []string{
		"module.ll",
		"-Ivendor/include",
		"-DFEATURE=1",
		"native.c",
		"-Lvendor/lib",
		"-lthing",
		"helper.o",
		"-o",
		"program",
	}
	testing.expect_value(t, len(command), tail_index + len(expected_tail))
	for value, index in expected_tail {
		testing.expect_value(t, command[tail_index + index], value)
	}
}

Fake_Cimport_State :: struct {
	calls:          int,
	available:      bool,
	infrastructure: bool,
	saw_options:    bool,
}

Conflict_Cimport_State :: struct {
	calls: int,
}

Symbol_Conflict_Cimport_State :: struct {
	calls: int,
}

fake_cimport_backend :: proc(user_data: rawptr, request: cimport.Request, allocator: mem.Allocator) -> cimport.Result {
	state := (^Fake_Cimport_State)(user_data)
	state.calls += 1
	state.saw_options =
		len(request.include_paths) == 2 &&
		request.include_paths[0] == "first/include" &&
		request.include_paths[1] == "second/include" &&
		len(request.defines) == 2 &&
		request.defines[0] == "FIRST=1" &&
		request.defines[1] == "SECOND" &&
		request.target == target.DEFAULT
	result := cimport.init_result(allocator)
	if !state.available {
		result.infrastructure = state.infrastructure
		result.error_message = fmt.aprintf("fake importer unavailable", allocator=allocator)
		return result
	}
	append(&result.types, cimport.Type{kind=.C_Int, child=cimport.INVALID_TYPE})
	append(&result.functions, cimport.Function{
		name=fmt.aprintf("fake_value", allocator=allocator),
		result=cimport.Type_Id(0),
		variadic=true,
		reason=fmt.aprintf("", allocator=allocator),
	})
	append(&result.variables, cimport.Variable{
		name=fmt.aprintf("fake_global", allocator=allocator),
		type=cimport.Type_Id(0),
		mutable=true,
		reason=fmt.aprintf("", allocator=allocator),
	})
	append(&result.macros, cimport.Macro_Constant{
		name=fmt.aprintf("FAKE_MAGIC", allocator=allocator),
		type=cimport.Type_Id(0),
		value={kind=.Integer, type=cimport.Type_Id(0), integer=7},
		reason=fmt.aprintf("", allocator=allocator),
	})
	result.available = true
	return result
}

conflict_cimport_backend :: proc(user_data: rawptr, request: cimport.Request, allocator: mem.Allocator) -> cimport.Result {
	state := (^Conflict_Cimport_State)(user_data)
	state.calls += 1
	result := cimport.init_result(allocator)
	kind := cimport.Type_Kind.C_Int
	if strings.has_suffix(request.path, "second.h") {
		kind = .C_Long
	}
	append(&result.types, cimport.Type{kind=kind, child=cimport.INVALID_TYPE})
	append(&result.variables, cimport.Variable{
		name=fmt.aprintf("conflict_global", allocator=allocator),
		type=cimport.Type_Id(0),
		mutable=true,
		reason=fmt.aprintf("", allocator=allocator),
	})
	result.available = true
	return result
}

symbol_conflict_cimport_backend :: proc(user_data: rawptr, request: cimport.Request, allocator: mem.Allocator) -> cimport.Result {
	state := (^Symbol_Conflict_Cimport_State)(user_data)
	state.calls += 1
	result := cimport.init_result(allocator)
	append(&result.types, cimport.Type{kind=.C_Int, child=cimport.INVALID_TYPE})
	if strings.has_suffix(request.path, "variable.h") {
		append(&result.variables, cimport.Variable{
			name=fmt.aprintf("conflict_symbol", allocator=allocator),
			type=cimport.Type_Id(0),
			mutable=true,
			reason=fmt.aprintf("", allocator=allocator),
		})
	} else {
		append(&result.functions, cimport.Function{
			name=fmt.aprintf("conflict_symbol", allocator=allocator),
			result=cimport.Type_Id(0),
			reason=fmt.aprintf("", allocator=allocator),
		})
	}
	result.available = true
	return result
}

main_conflict_cimport_backend :: proc(_: rawptr, _: cimport.Request, allocator: mem.Allocator) -> cimport.Result {
	result := cimport.init_result(allocator)
	append(&result.types, cimport.Type{kind=.C_Int, child=cimport.INVALID_TYPE})
	append(&result.variables, cimport.Variable{
		name=fmt.aprintf("main", allocator=allocator),
		type=cimport.Type_Id(0),
		mutable=true,
		reason=fmt.aprintf("", allocator=allocator),
	})
	result.available = true
	return result
}

write_conflict_cimport_backend :: proc(_: rawptr, _: cimport.Request, allocator: mem.Allocator) -> cimport.Result {
	result := cimport.init_result(allocator)
	append(&result.types, cimport.Type{kind=.C_Int, child=cimport.INVALID_TYPE})
	append(&result.variables, cimport.Variable{
		name=fmt.aprintf("write", allocator=allocator),
		type=cimport.Type_Id(0),
		mutable=true,
		reason=fmt.aprintf("", allocator=allocator),
	})
	result.available = true
	return result
}

count_substring_occurrences :: proc(text, needle: string) -> int {
	if len(needle) == 0 {
		return 0
	}
	count := 0
	for index := 0; index + len(needle) <= len(text); index += 1 {
		if text[index:index + len(needle)] == needle {
			count += 1
		}
	}
	return count
}

find_substring_offset :: proc(text, needle: string) -> int {
	if len(needle) == 0 {
		return 0
	}
	for index := 0; index + len(needle) <= len(text); index += 1 {
		if text[index:index + len(needle)] == needle {
			return index
		}
	}
	return -1
}

find_cimport_variable :: proc(result: ^cimport.Result, name: string) -> (^cimport.Variable, bool) {
	for &variable in result.variables {
		if variable.name == name {
			return &variable, true
		}
	}
	return nil, false
}

count_cimport_variables :: proc(result: ^cimport.Result, name: string) -> int {
	count := 0
	for variable in result.variables {
		if variable.name == name {
			count += 1
		}
	}
	return count
}

find_cimport_macro :: proc(result: ^cimport.Result, name: string) -> (^cimport.Macro_Constant, bool) {
	for &macro in result.macros {
		if macro.name == name {
			return &macro, true
		}
	}
	return nil, false
}

cimport_has_named_result :: proc(result: ^cimport.Result, name: string) -> bool {
	if _, ok := find_cimport_macro(result, name); ok {
		return true
	}
	for item in result.unsupported {
		if item.name == name {
			return true
		}
	}
	return false
}

@(test)
cimport_backend_is_replaceable :: proc(t: ^testing.T) {
	state := Fake_Cimport_State{available=true}
	options := cimport.Options{backend={import_header=fake_cimport_backend, user_data=&state}}
	result := cimport.import_header(options, "fake.h")
	defer cimport.destroy_result(&result)

	testing.expect(t, result.available)
	testing.expect_value(t, state.calls, 1)
	testing.expect_value(t, len(result.functions), 1)
	testing.expect_value(t, len(result.variables), 1)
	testing.expect_value(t, len(result.macros), 1)
	testing.expect_value(t, result.functions[0].name, "fake_value")
	testing.expect_value(t, result.variables[0].name, "fake_global")
	testing.expect_value(t, result.macros[0].name, "FAKE_MAGIC")
	testing.expect(t, result.functions[0].variadic)
}

@(test)
libclang_import_preserves_external_object_and_final_macro_semantics :: proc(t: ^testing.T) {
	options := cimport.Options{
		include_paths=[]string{"examples/interop/header/include"},
		defines=[]string{"BROLANG_FEATURE"},
	}
	result := cimport.import_header(
		options,
		"examples/interop/header/include/native.h",
		target.DEFAULT,
	)
	defer cimport.destroy_result(&result)

	testing.expect(t, result.available)
	testing.expect_value(t, result.error_message, "")

	enum_alias_type := cimport.INVALID_TYPE
	for alias in result.aliases {
		if alias.name == "Imported_Enum" {
			enum_alias_type = alias.type
			break
		}
	}
	testing.expect(t, enum_alias_type != cimport.INVALID_TYPE)
	if enum_alias_type != cimport.INVALID_TYPE {
		testing.expect_value(t, result.types[enum_alias_type].kind, cimport.Type_Kind.C_Int)
	}
	enum_negative, found_enum_negative := find_cimport_macro(&result, "IMPORTED_ENUM_NEGATIVE")
	enum_same, found_enum_same := find_cimport_macro(&result, "IMPORTED_ENUM_SAME")
	enum_value, found_enum_value := find_cimport_macro(&result, "IMPORTED_ENUM_VALUE")
	enum_back, found_enum_back := find_cimport_macro(&result, "IMPORTED_ENUM_BACK")
	enum_anon, found_enum_anon := find_cimport_macro(&result, "IMPORTED_ANON_ENUM")
	testing.expect(t, found_enum_negative && found_enum_same && found_enum_value && found_enum_back && found_enum_anon)
	if found_enum_negative {
		testing.expect(t, enum_negative.value.negative)
		testing.expect_value(t, enum_negative.value.integer, u64(2))
	}
	if found_enum_same {
		testing.expect(t, enum_same.value.negative)
		testing.expect_value(t, enum_same.value.integer, u64(2))
	}
	if found_enum_value {
		testing.expect(t, !enum_value.value.negative)
		testing.expect_value(t, enum_value.value.integer, u64(7))
	}
	if found_enum_back {
		testing.expect_value(t, enum_back.value.integer, u64(3))
	}
	if found_enum_anon {
		testing.expect_value(t, enum_anon.value.integer, u64(9))
	}

	tls, found_tls := find_cimport_variable(&result, "imported_tls_global")
	testing.expect(t, found_tls)
	if found_tls {
		testing.expect(t, strings.contains(tls.reason, "thread-local C variables are not supported"))
	}

	const_array, found_const_array := find_cimport_variable(&result, "imported_const_array")
	testing.expect(t, found_const_array)
	if found_const_array {
		testing.expect(t, !const_array.mutable)
		testing.expect(t, const_array.type != cimport.INVALID_TYPE)
		if const_array.type != cimport.INVALID_TYPE {
			array_type := result.types[const_array.type]
			testing.expect_value(t, array_type.kind, cimport.Type_Kind.Array)
			testing.expect(t, array_type.child != cimport.INVALID_TYPE)
			if array_type.child != cimport.INVALID_TYPE {
				testing.expect_value(t, result.types[array_type.child].kind, cimport.Type_Kind.C_Int)
			}
		}
	}

	typedef_const_array, found_typedef_const_array := find_cimport_variable(
		&result, "imported_typedef_const_array",
	)
	testing.expect(t, found_typedef_const_array)
	if found_typedef_const_array {
		testing.expect(t, !typedef_const_array.mutable)
		testing.expect_value(t, typedef_const_array.reason, "")
		testing.expect(t, typedef_const_array.type != cimport.INVALID_TYPE)
		if typedef_const_array.type != cimport.INVALID_TYPE {
			array_type := result.types[typedef_const_array.type]
			testing.expect_value(t, array_type.kind, cimport.Type_Kind.Array)
			testing.expect(t, !array_type.mutable)
			testing.expect_value(t, array_type.count, u64(2))
		}
	}

	redeclared_array, found_redeclared_array := find_cimport_variable(
		&result, "imported_redeclared_array",
	)
	testing.expect(t, found_redeclared_array)
	testing.expect_value(t, count_cimport_variables(&result, "imported_redeclared_array"), 1)
	if found_redeclared_array {
		testing.expect_value(t, redeclared_array.reason, "")
		testing.expect(t, redeclared_array.type != cimport.INVALID_TYPE)
		if redeclared_array.type != cimport.INVALID_TYPE {
			array_type := result.types[redeclared_array.type]
			testing.expect_value(t, array_type.kind, cimport.Type_Kind.Array)
			testing.expect_value(t, array_type.count, u64(4))
		}
	}

	repeated, found_repeated := find_cimport_macro(&result, "IMPORTED_REPEAT")
	testing.expect(t, found_repeated)
	if found_repeated {
		testing.expect_value(t, repeated.value.integer, u64(123))
	}
	testing.expect(t, !cimport_has_named_result(&result, "IMPORTED_GUARDED"))
	testing.expect(t, !cimport_has_named_result(&result, "IMPORTED_ONCE"))

	negative_decimal, found_negative_decimal := find_cimport_macro(&result, "IMPORTED_NEG_DECIMAL")
	testing.expect(t, found_negative_decimal)
	if found_negative_decimal {
		testing.expect_value(t, result.types[negative_decimal.type].kind, cimport.Type_Kind.C_Long)
		testing.expect_value(t, negative_decimal.value.integer, u64(2147483648))
		testing.expect(t, negative_decimal.value.negative)
	}

	negative_hex, found_negative_hex := find_cimport_macro(&result, "IMPORTED_NEG_HEX")
	testing.expect(t, found_negative_hex)
	if found_negative_hex {
		testing.expect_value(t, result.types[negative_hex.type].kind, cimport.Type_Kind.C_Uint)
		testing.expect_value(t, negative_hex.value.integer, u64(0x80000000))
		testing.expect(t, !negative_hex.value.negative)
	}

	negative_uint, found_negative_uint := find_cimport_macro(&result, "IMPORTED_NEG_UINT")
	testing.expect(t, found_negative_uint)
	if found_negative_uint {
		testing.expect_value(t, result.types[negative_uint.type].kind, cimport.Type_Kind.C_Uint)
		testing.expect_value(t, negative_uint.value.integer, u64(0xffffffff))
		testing.expect(t, !negative_uint.value.negative)
	}

	conversions, found_conversions := find_cimport_macro(&result, "IMPORTED_CONVERSIONS")
	testing.expect(t, found_conversions)
	if found_conversions {
		testing.expect_value(t, len(conversions.values), 5)
		expected_kinds := [?]cimport.Type_Kind{
			.C_Int,
			.C_Double,
			.C_Int,
			.C_Float,
			.C_Int,
		}
		for value, index in conversions.values {
			testing.expect(t, value.type != cimport.INVALID_TYPE)
			if value.type != cimport.INVALID_TYPE {
				testing.expect_value(t, result.types[value.type].kind, expected_kinds[index])
			}
		}
	}
}

@(test)
final_macros_override_same_named_c_value_declarations :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	c_options := cimport.Options{
		include_paths=[]string{"examples/interop/header/include"},
		defines=[]string{"BROLANG_FEATURE"},
	}
	module, loaded := loader.load(
		"examples/interop/header/app",
		&sources,
		&diagnostics,
		&symbols,
		c_options=c_options,
	)
	defer ast.destroy_module(&module)
	testing.expect(t, loaded)

	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, !strings.contains(llvm_text, "@IMPORTED_SHADOW_OBJECT = external"))
	testing.expect(t, !strings.contains(llvm_text, "declare i32 @IMPORTED_SHADOW_FUNCTION("))
	testing.expect(t, !strings.contains(llvm_text, "@IMPORTED_SHADOW_UNSUPPORTED = external"))
	testing.expect(t, !strings.contains(llvm_text, "@IMPORTED_EMPTY_SHADOW = external"))
}

@(test)
static_inline_c_functions_route_through_generated_trampolines :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	c_options := cimport.Options{
		include_paths=[]string{"examples/interop/header/include"},
		defines=[]string{"BROLANG_FEATURE"},
	}
	module, loaded := loader.load(
		"examples/interop/header/app",
		&sources,
		&diagnostics,
		&symbols,
		c_options=c_options,
	)
	defer ast.destroy_module(&module)
	testing.expect(t, loaded)

	// Symbols are namespaced by a header-path hash, so match by suffix.
	scalar_symbol := ""
	record_symbol := ""
	for trampoline in module.c_trampolines {
		testing.expect(t, strings.has_prefix(trampoline.symbol, "__brolang_inline_"))
		if strings.has_suffix(trampoline.symbol, "_imported_inline") {
			scalar_symbol = trampoline.symbol
		}
		if strings.has_suffix(trampoline.symbol, "_imported_inline_record") {
			record_symbol = trampoline.symbol
		}
		// The variadic static inline is unsupported and must not be wrapped.
		testing.expect(t, !strings.has_suffix(trampoline.symbol, "_imported_inline_variadic"))
	}
	testing.expect(t, scalar_symbol != "")
	testing.expect(t, record_symbol != "")

	// A static inline whose signature translates but is rejected by the loader's
	// by-value layout checks keeps its cimport-assigned link_name yet must not
	// emit a wrapper — it is uncallable, so the wrapper would be dead code.
	bad_layout_link := ""
	for function in module.functions {
		if symbol.resolve(&symbols, function.name) == "imported_inline_bad_layout" {
			testing.expect(t, len(function.unsupported_reason) > 0)
			bad_layout_link = function.link_name
		}
	}
	testing.expect(t, bad_layout_link != "") // cimport did generate a wrapper symbol
	for trampoline in module.c_trampolines {
		testing.expect(t, trampoline.symbol != bad_layout_link)
	}

	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, fmt.tprintf("@%s(", scalar_symbol)))
	testing.expect(t, strings.contains(llvm_text, fmt.tprintf("@%s(", record_symbol)))
	// The internal-linkage C symbol itself is never declared or called directly.
	testing.expect(t, !strings.contains(llvm_text, "@imported_inline("))
}

@(test)
loader_injects_and_caches_cimport_backend_per_compilation :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	state := Fake_Cimport_State{available=true}
	options := cimport.Options{
		include_paths=[]string{"first/include", "second/include"},
		defines=[]string{"FIRST=1", "SECOND"},
		backend={import_header=fake_cimport_backend, user_data=&state},
	}
	module, loaded := loader.load(
		"examples/interop/header_cache",
		&sources,
		&diagnostics,
		&symbols,
		c_options=options,
	)
	defer ast.destroy_module(&module)

	testing.expect(t, loaded)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, state.calls, 1)
	testing.expect(t, state.saw_options)
	testing.expect_value(t, len(module.imports), 2)
	testing.expect_value(t, module.imports[0].target, module.imports[1].target)
	testing.expect_value(t, len(module.functions), 2)
	found_variadic := false
	for function in module.functions {
		found_variadic = found_variadic || function.variadic
	}
	testing.expect(t, found_variadic)
	found_external := false
	found_macro := false
	for global in module.globals {
		name := symbol.resolve(&symbols, global.name)
		found_external = found_external || (name == "fake_global" && global.external && global.writable)
		found_macro = found_macro || name == "FAKE_MAGIC"
	}
	testing.expect(t, found_external)
	testing.expect(t, found_macro)
}

@(test)
conflicting_external_c_globals_are_diagnosed_and_deduped :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	state := Conflict_Cimport_State{}
	options := cimport.Options{backend={import_header=conflict_cimport_backend, user_data=&state}}
	module, loaded := loader.load(
		"examples/interop/header_conflict",
		&sources,
		&diagnostics,
		&symbols,
		c_options=options,
	)
	defer ast.destroy_module(&module)
	testing.expect(t, loaded)
	testing.expect_value(t, state.calls, 2)

	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	found_conflict := false
	for diagnostic in diagnostics.items {
		if strings.contains(diagnostic.message, "conflicting external C variable declarations for 'conflict_global'") {
			found_conflict = true
		}
	}
	testing.expect(t, found_conflict)
	testing.expect_value(t, count_substring_occurrences(llvm_text, "@conflict_global = external global"), 1)
	testing.expect(t, strings.contains(llvm_text, "@conflict_global = external global i32"))
	testing.expect(t, !strings.contains(llvm_text, "@conflict_global = external global i64"))
}

@(test)
external_c_global_and_function_link_name_conflict_is_diagnosed :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	state := Symbol_Conflict_Cimport_State{}
	options := cimport.Options{backend={import_header=symbol_conflict_cimport_backend, user_data=&state}}
	module, loaded := loader.load(
		"examples/interop/header_symbol_conflict",
		&sources,
		&diagnostics,
		&symbols,
		c_options=options,
	)
	defer ast.destroy_module(&module)
	testing.expect(t, loaded)
	testing.expect_value(t, state.calls, 2)

	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	found_conflict := false
	for diagnostic in diagnostics.items {
		if strings.contains(diagnostic.message, "external C variable 'conflict_symbol' conflicts with a C function declaration") {
			found_conflict = true
		}
	}
	testing.expect(t, found_conflict)
	testing.expect(t, !strings.contains(llvm_text, "@conflict_symbol = external global"))
	testing.expect(t, strings.contains(llvm_text, "declare i32 @conflict_symbol()"))
	testing.expect(t, !strings.contains(llvm_text, "load i32, ptr @conflict_symbol"))
}

@(test)
external_c_global_named_main_is_omitted_for_root_entry_point :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	options := cimport.Options{backend={import_header=main_conflict_cimport_backend}}
	module, loaded := loader.load(
		"examples/interop/header_main_conflict",
		&sources,
		&diagnostics,
		&symbols,
		c_options=options,
	)
	defer ast.destroy_module(&module)
	testing.expect(t, loaded)

	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	found_conflict := false
	for diagnostic in diagnostics.items {
		found_conflict =
			found_conflict ||
			strings.contains(
				diagnostic.message,
				"external C variable 'main' conflicts with the program entry point",
			)
	}
	testing.expect(t, found_conflict)
	testing.expect_value(t, count_substring_occurrences(llvm_text, "define i32 @main("), 1)
	testing.expect(t, !strings.contains(llvm_text, "@main = external"))
}

@(test)
external_c_global_named_main_is_omitted_for_synthesized_entry_point :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	options := cimport.Options{backend={import_header=main_conflict_cimport_backend}}
	module, loaded := loader.load(
		"examples/interop/header_main_conflict_missing",
		&sources,
		&diagnostics,
		&symbols,
		c_options=options,
	)
	defer ast.destroy_module(&module)
	testing.expect(t, loaded)

	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	found_conflict := false
	found_missing_main := false
	for diagnostic in diagnostics.items {
		found_conflict =
			found_conflict ||
			strings.contains(
				diagnostic.message,
				"external C variable 'main' conflicts with the program entry point",
			)
		found_missing_main =
			found_missing_main ||
			strings.contains(diagnostic.message, "missing or unusable main function")
	}
	testing.expect(t, found_conflict)
	testing.expect(t, found_missing_main)
	testing.expect_value(t, count_substring_occurrences(llvm_text, "define i32 @main("), 1)
	testing.expect(t, !strings.contains(llvm_text, "@main = external"))
}

@(test)
external_c_global_named_write_is_omitted_for_compiler_runtime :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	options := cimport.Options{backend={import_header=write_conflict_cimport_backend}}
	module, loaded := loader.load(
		"examples/interop/header_write_conflict",
		&sources,
		&diagnostics,
		&symbols,
		c_options=options,
	)
	defer ast.destroy_module(&module)
	testing.expect(t, loaded)

	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	found_conflict := false
	for diagnostic in diagnostics.items {
		found_conflict =
			found_conflict ||
			strings.contains(
				diagnostic.message,
				"external C variable 'write' conflicts with the compiler runtime",
			)
	}
	testing.expect(t, found_conflict)
	testing.expect_value(t, count_substring_occurrences(llvm_text, "declare i64 @write("), 1)
	testing.expect(t, !strings.contains(llvm_text, "@write = external"))
	testing.expect(t, strings.contains(llvm_text, "call void @bro.trap"))
}

@(test)
tls_reference_and_const_external_array_assignment_are_diagnosed :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	c_options := cimport.Options{include_paths=[]string{"examples/interop/header/include"}}
	module, loaded := loader.load(
		"examples/interop/header_unsupported",
		&sources,
		&diagnostics,
		&symbols,
		c_options=c_options,
	)
	defer ast.destroy_module(&module)
	testing.expect(t, loaded)

	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	found_tls := false
	found_excess_aggregate := false
	found_signed_narrow := false
	found_shadowed_unsupported := false
	found_float_overflow := false
	found_empty_shadow := false
	found_inline_variadic := false
	not_writable_count := 0
	for diagnostic in diagnostics.items {
		found_tls =
			found_tls ||
			strings.contains(
				diagnostic.message,
				"C declaration 'imported_tls_global' is unavailable: thread-local C variables are not supported",
			)
		found_excess_aggregate =
			found_excess_aggregate ||
			strings.contains(
				diagnostic.message,
				"C declaration 'IMPORTED_TOO_MANY_COLOR' is unavailable: C macro aggregate initializer is not representable",
			)
		found_signed_narrow =
			found_signed_narrow ||
			strings.contains(
				diagnostic.message,
				"C declaration 'IMPORTED_SIGNED_NARROW_BAD' is unavailable: C macro aggregate initializer is not representable",
			)
		found_shadowed_unsupported =
			found_shadowed_unsupported ||
			strings.contains(
				diagnostic.message,
				"C declaration 'IMPORTED_SHADOW_UNSUPPORTED' is unavailable: C macro is not a supported constant",
			)
		found_float_overflow =
			found_float_overflow ||
			strings.contains(
				diagnostic.message,
				"C declaration 'IMPORTED_FLOAT_OVERFLOW' is unavailable: C macro is not a supported constant",
			)
		found_empty_shadow =
			found_empty_shadow ||
			strings.contains(
				diagnostic.message,
				"C declaration 'IMPORTED_EMPTY_SHADOW' is unavailable: C macro has no replacement value",
			)
		found_inline_variadic =
			found_inline_variadic ||
			strings.contains(
				diagnostic.message,
				"C declaration 'imported_inline_variadic' is unavailable: variadic static inline C functions are not supported",
			)
		if strings.contains(diagnostic.message, "assignment target is not writable") {
			not_writable_count += 1
		}
	}
	testing.expect(t, found_tls)
	testing.expect(t, found_excess_aggregate)
	testing.expect(t, found_signed_narrow)
	testing.expect(t, found_shadowed_unsupported)
	testing.expect(t, found_float_overflow)
	testing.expect(t, found_empty_shadow)
	testing.expect(t, found_inline_variadic)
	testing.expect(t, not_writable_count >= 5)
	testing.expect(t, !strings.contains(llvm_text, "@IMPORTED_EMPTY_SHADOW = external"))
	testing.expect(
		t,
		strings.contains(
			llvm_text,
			"@imported_typedef_const_array = external constant [2 x i32]",
		),
	)
	testing.expect_value(
		t,
		count_substring_occurrences(
			llvm_text,
			"@imported_redeclared_array = external global [4 x i32]",
		),
		1,
	)
	testing.expect(
		t,
		!strings.contains(
			llvm_text,
			"ptr @imported_const_array_record, i64 0",
		),
	)
	testing.expect(t, !strings.contains(llvm_text, "@IMPORTED_SHADOW_UNSUPPORTED = external"))
}

@(test)
cimport_infrastructure_failure_makes_compilation_unavailable :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	state := Fake_Cimport_State{infrastructure=true}
	options := cimport.Options{backend={import_header=fake_cimport_backend, user_data=&state}}
	module, loaded := loader.load(
		"examples/interop/header_cache",
		&sources,
		&diagnostics,
		&symbols,
		c_options=options,
	)
	defer ast.destroy_module(&module)

	testing.expect(t, !loaded)
	testing.expect_value(t, state.calls, 1)
	testing.expect(t, len(diagnostics.items) > 0)
}

@(test)
source_store_owns_buffers_indexes_lines_and_deduplicates_diagnostics :: proc(t: ^testing.T) {
	store := source.init_store()
	defer source.destroy_store(&store)
	bytes := make([]byte, len("one\ntwo\n"))
	copy(bytes, "one\ntwo\n")
	source_id := source.add_source_owned(&store, "owned.bro", bytes)
	bytes[0] = 'O'

	diagnostics := source.init_store_diagnostics(&store)
	defer source.destroy_diagnostics(&diagnostics)
	span := source.Span{file=source_id, start=4, end=7}
	first := source.add(&diagnostics, span, "same")
	second := source.addf(&diagnostics, span, "%s", "same")
	other := source.add(&diagnostics, span, "other")
	formatted := source.format(&diagnostics, other)
	defer delete(formatted)

	testing.expect_value(t, store.items[source_id].text, "One\ntwo\n")
	testing.expect_value(t, len(store.items[source_id].line_starts), 3)
	testing.expect_value(t, first, second)
	testing.expect_value(t, len(diagnostics.items), 2)
	testing.expect(t, strings.contains(formatted, "--> owned.bro:2:1"))
}

@(test)
diagnostic_warnings_format_and_dedupe_by_severity :: proc(t: ^testing.T) {
	source_file := source.Source{path="test.bro", text="one\n"}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	span := source.Span{start=0, end=3}

	warning := source.add_warning(&diagnostics, span, "same")
	warning_again := source.addf_warning(&diagnostics, span, "%s", "same")
	err := source.add(&diagnostics, span, "same")
	formatted_warning := source.format(&diagnostics, warning)
	defer delete(formatted_warning)
	formatted_error := source.format(&diagnostics, err)
	defer delete(formatted_error)

	testing.expect_value(t, warning, warning_again)
	testing.expect(t, warning != err)
	testing.expect_value(t, len(diagnostics.items), 2)
	testing.expect_value(t, diagnostics.items[warning].severity, source.Severity.Warning)
	testing.expect_value(t, diagnostics.items[err].severity, source.Severity.Error)
	testing.expect(t, strings.contains(formatted_warning, "warning: same\n --> test.bro:1:1"))
	testing.expect(t, strings.contains(formatted_error, "error: same\n --> test.bro:1:1"))
}

@(test)
rich_diagnostics_render_labels_notes_help_and_tabs :: proc(t: ^testing.T) {
	store := source.init_store()
	defer source.destroy_store(&store)
	primary_file := source.add_source(&store, "main.bro", "\tmissing()\nnext()\n")
	definition_file := source.add_source(&store, "dep.bro", "value :: 1\n")
	diagnostics := source.init_store_diagnostics(&store)
	defer source.destroy_diagnostics(&diagnostics)
	id := source.add(&diagnostics, source.Span{file=primary_file, start=1, end=8}, "unknown symbol 'missing'")
	source.set_primary_label(&diagnostics, id, "unknown symbol")
	source.set_primary_label(&diagnostics, id, "unknown symbol")
	source.add_secondary_label(
		&diagnostics, id,
		source.Span{file=definition_file, start=0, end=5},
		"related declaration",
	)
	source.add_note(&diagnostics, id, "names resolve in the current scope")
	source.add_note(&diagnostics, id, "names resolve in the current scope")
	source.add_help(&diagnostics, id, "declare 'missing' before using it")
	formatted := source.format(&diagnostics, id)
	defer delete(formatted)
	multiline := source.add(
		&diagnostics,
		source.Span{file=primary_file, start=1, end=17},
		"multiline failure",
	)
	multiline_formatted := source.format(&diagnostics, multiline)
	defer delete(multiline_formatted)
	unknown := source.add(&diagnostics, source.Span{}, "no location")
	unknown_formatted := source.format(&diagnostics, unknown)
	defer delete(unknown_formatted)

	testing.expect_value(t, len(diagnostics.annotations), 4)
	testing.expect(t, strings.contains(formatted, "error: unknown symbol 'missing'"))
	testing.expect(t, strings.contains(formatted, "--> main.bro:1:2"))
	testing.expect(t, strings.contains(formatted, "^^^^^^^ unknown symbol"))
	testing.expect(t, strings.contains(formatted, "::: dep.bro:1:1"))
	testing.expect(t, strings.contains(formatted, "----- related declaration"))
	testing.expect(t, strings.contains(formatted, "note: names resolve in the current scope"))
	testing.expect(t, strings.contains(formatted, "help: declare 'missing' before using it"))
	testing.expect(t, strings.contains(multiline_formatted, "1 |     missing()"))
	testing.expect(t, !strings.contains(multiline_formatted, "next()"))
	testing.expect_value(t, unknown_formatted, "main.bro: error: no location")
}

@(test)
poisoned_expressions_preserve_independent_root_diagnostics :: proc(t: ^testing.T) {
	text := `bad :: missing_global
sink func(value i32) void { _ = value }
broken func(value int) int { return missing_return + value }
main func() void {
	_ = missing_add + 1
	_ = try missing_try()
	missing_catch() catch |_| {}
	sink(missing_arg)
	missing_stmt()
	missing_target.field = 1
	value i32 = 0
	value += missing_rhs
	_ = broken(1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 9)
	for diagnostic in diagnostics.items {
		testing.expect(t, strings.has_prefix(diagnostic.message, "unknown symbol 'missing_"))
		testing.expect(t, !strings.contains(diagnostic.message, "fallible expression"))
		testing.expect(t, !strings.contains(diagnostic.message, "must be consumed"))
		testing.expect(t, !strings.contains(diagnostic.message, "compatible numeric operands"))
		testing.expect(t, !strings.contains(diagnostic.message, "implicitly convert"))
	}
}

@(test)
maximum_signed_i64_literal_parses_exactly :: proc(t: ^testing.T) {
	source_file := source.Source{path="test.bro", text="value :: 9223372036854775807\nmain func() void {}\n"}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, module.exprs[module.globals[0].expr].integer, u64(9223372036854775807))
}

@(test)
negative_constants_fold_and_accept_signed_i64_minimum :: proc(t: ^testing.T) {
	text := `minimum :: -9223372036854775808
grouped i64 :: -(9223372036854775808)
folded :: -(1 + 2)
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, types.equal(hir_module.globals[0].type, types.I64))
	testing.expect(t, types.equal(hir_module.globals[1].type, types.I64))
	testing.expect(t, types.equal(hir_module.globals[2].type, types.I8))
	testing.expect_value(t, hir_module.globals[0].static_value, i64(-9223372036854775807-1))
	testing.expect_value(t, hir_module.globals[1].static_value, i64(-9223372036854775807-1))
	testing.expect_value(t, hir_module.globals[2].static_value, i64(-3))
}

@(test)
constant_division_by_zero_has_a_precise_diagnostic :: proc(t: ^testing.T) {
	text := `value :: divtrunc!(5, 0)
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_division_by_zero := false
	found_overflow := false
	for diagnostic in diagnostics.items {
		found_division_by_zero = found_division_by_zero ||
		                         strings.contains(diagnostic.message, "division builtin denominator is zero")
		found_overflow = found_overflow ||
		                 strings.contains(diagnostic.message, "integer constant expression exceeds signed i64 range")
	}
	testing.expect(t, found_division_by_zero)
	testing.expect(t, !found_overflow)
}

@(test)
out_of_range_negative_constants_are_diagnosed :: proc(t: ^testing.T) {
	text := `positive :: 9223372036854775808
below_minimum :: -9223372036854775809
double_minimum :: --9223372036854775808
maximum_u64 :: 18446744073709551615
beyond_u64 :: 18446744073709551616
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_expression_range := 0
	found_literal_range := 0
	found_u64_range := false
	for diagnostic in diagnostics.items {
		found_expression_range += 1 if strings.contains(diagnostic.message, "exceeds signed i64 range") else 0
		found_literal_range += 1 if strings.contains(diagnostic.message, "does not fit in i64") else 0
		found_u64_range = found_u64_range || strings.contains(diagnostic.message, "magnitude does not fit in u64")
	}
	testing.expect_value(t, found_expression_range, 2)
	testing.expect_value(t, found_literal_range, 2)
	testing.expect(t, found_u64_range)
}

@(test)
runtime_negation_preserves_operand_type_before_result_widening :: proc(t: ^testing.T) {
	text := `negate_i8 func(value i8) i8 {
	return -value
}
widen_after_negate func(value i8) i16 {
	return -value
}
main func() void {
	_ = negate_i8(1)
	_ = widen_after_negate(1)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "@llvm.ssub.with.overflow.i8"))
	found_widen := false
	for function in hir_module.functions {
		if symbol.resolve(&symbols, function.name) != "widen_after_negate" {
			continue
		}
		statement := hir_module.statements[function.body[0]]
		widen := hir_module.exprs[statement.expr]
		negate := hir_module.exprs[widen.left]
		testing.expect_value(t, widen.kind, hir.Expr_Kind.Widen)
		testing.expect(t, types.equal(widen.type, types.I16))
		testing.expect_value(t, negate.kind, hir.Expr_Kind.Negate)
		testing.expect(t, types.equal(negate.type, types.I8))
		found_widen = true
	}
	testing.expect(t, found_widen)
}

@(test)
malformed_hir_references_lower_to_valid_trapped_llvm :: proc(t: ^testing.T) {
	hir_module := hir.init_module()
	defer hir.destroy_module(&hir_module)
	append(&hir_module.exprs, hir.Expr{
		kind=.Local,
		type=types.I8,
		target=hir.local_ref(hir.INVALID_LOCAL),
		left=hir.INVALID_EXPR,
		right=hir.INVALID_EXPR,
		diagnostic=source.INVALID_DIAGNOSTIC,
	})
	append(&hir_module.statements, hir.Stmt{
		kind=.Expression,
		expr=hir.Expr_Id(0),
		local=hir.INVALID_LOCAL,
		diagnostic=source.INVALID_DIAGNOSTIC,
	})
	body := make([]hir.Stmt_Id, 1)
	body[0] = hir.Stmt_Id(0)
	append(&hir_module.functions, hir.Function{
		name=symbol.INVALID,
		link_name=strings.clone("main"),
		calling_convention=.C,
		implementation=.Definition,
		linkage=.External,
		is_main=true,
		result=types.VOID,
		body=body,
		diagnostic=source.INVALID_DIAGNOSTIC,
	})
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	source_file := source.Source{path="test.bro", text=""}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(text)

	testing.expect(t, strings.contains(text, "call void @bro.trap"))
	testing.expect(t, !strings.contains(text, "%v-1"))
}

@(test)
malformed_ir_emits_traps_and_typed_sentinels :: proc(t: ^testing.T) {
	module := ir.init_module()
	defer ir.destroy_module(&module)
	instructions := make([]ir.Instruction, 11)
	instructions[0] = ir.Instruction{op=.Store, type=types.I8, a=ir.INVALID_INSTRUCTION, b=ir.INVALID_INSTRUCTION, diagnostic=source.INVALID_DIAGNOSTIC}
	instructions[1] = ir.Instruction{op=.Add_Checked, type=types.I32, a=ir.INVALID_INSTRUCTION, b=ir.INVALID_INSTRUCTION, diagnostic=source.INVALID_DIAGNOSTIC}
	instructions[2] = ir.Instruction{op=.Neg_Checked, type=types.I16, a=ir.INVALID_INSTRUCTION, b=ir.INVALID_INSTRUCTION, diagnostic=source.INVALID_DIAGNOSTIC}
	division_ops := [?]ir.Opcode{
		.Div_Checked,
		.Div_Trunc_Checked, .Div_Floor_Checked, .Div_Exact_Checked, .Div_Ceil_Checked,
		.Rem_Checked, .Mod_Checked,
	}
	for op, index in division_ops {
		instructions[3+index] = ir.Instruction{op=op, type=types.I32, a=ir.INVALID_INSTRUCTION, b=ir.INVALID_INSTRUCTION, diagnostic=source.INVALID_DIAGNOSTIC}
	}
	instructions[10] = ir.Instruction{op=.Return, type=types.I32, a=ir.Instruction_Id(1), b=ir.INVALID_INSTRUCTION, diagnostic=source.INVALID_DIAGNOSTIC}
	append(&module.functions, ir.Function{
		link_name=strings.clone("main"),
		calling_convention=.C,
		implementation=.Definition,
		linkage=.External,
		is_main=true,
		result=types.I32,
		instructions=instructions,
	})
	source_file := source.Source{path="test.bro", text=""}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	text := llvm.emit(&module, &diagnostics, &symbols)
	defer delete(text)

	testing.expect(t, strings.contains(text, "call void @bro.trap"))
	testing.expect(t, strings.contains(text, "%v0 = add i8 0, -86"))
	testing.expect(t, strings.contains(text, "%v1 = add i32 0, -1431655766"))
	testing.expect(t, strings.contains(text, "%v2 = add i16 0, -21846"))
	for index in 3..=9 {
		testing.expect(t, strings.contains(text, fmt.tprintf("%%v%d = add i32 0, -1431655766", index)))
	}
	testing.expect(t, strings.contains(text, "@bro.trap(ptr %message, i64 %length) noreturn"))
	testing.expect(t, !strings.contains(text, "%v-1"))
	llvm_path := "/tmp/brolang-test-malformed-recovery.ll"
	output := "/tmp/brolang-test-malformed-recovery"
	defer _ = os.remove(llvm_path)
	defer _ = os.remove(output)
	testing.expect(t, os.write_entire_file(llvm_path, transmute([]byte)text))
	testing.expect(t, backend.compile(llvm_path, output))
}

@(test)
hundred_thousand_term_runtime_addition_uses_iterative_pipeline :: proc(t: ^testing.T) {
	builder := strings.builder_make()
	defer strings.builder_destroy(&builder)
	strings.write_string(&builder, "sum func(value i32) i32 { return value")
	for _ in 0..<100_000 {
		strings.write_string(&builder, " + 1")
	}
	strings.write_string(&builder, " }\nmain func() void { _ = sum(0) }\n")
	source_file := source.Source{path="test.bro", text=strings.to_string(builder)}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)

	instruction_count := 0
	for function in ir_module.functions {
		instruction_count += len(function.instructions)
	}
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, instruction_count > 100_000)
}

@(test)
global_cycle_diagnostic_reports_endpoint_lines :: proc(t: ^testing.T) {
	text := `a i32 :: b
b i32 :: a
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for _, diagnostic_index in diagnostics.items {
		message := source.format(&diagnostics, source.diagnostic_id(diagnostic_index))
		found = found || strings.contains(message, "global initialization cycle from 'a' at test.bro:1 to 'b' at test.bro:2")
		delete(message)
	}
	testing.expect(t, found)
}

@(test)
deep_global_cycle_detection_uses_iterative_dfs :: proc(t: ^testing.T) {
	count := 50_000
	ast_module := ast.init_module()
	defer ast.destroy_module(&ast_module)
	source_file := source.Source{path="test.bro", text=""}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	name := symbol.intern(&symbols, "value")
	state := checker.Checker{
		ast_module=&ast_module,
		diagnostics=&diagnostics,
		symbols=&symbols,
		module=hir.init_module(),
		allocator=context.allocator,
	}
	defer hir.destroy_module(&state.module)
	defer delete(state.cycle_stack)

	for id in 0..<count {
		append(&ast_module.globals, ast.Global{name=name})
		dependencies: [dynamic]hir.Global_Id
		dependencies.allocator = context.allocator
		append(&dependencies, hir.global_id((id+1)%count))
		append(&state.module.globals, hir.Global{name=name, dependencies=dependencies})
	}
	states := make([]u8, count)
	defer delete(states)
	checker.detect_global_cycles_visit(&state, hir.Global_Id(0), states)

	testing.expect_value(t, len(diagnostics.items), 1)
	for global in state.module.globals {
		testing.expect(t, global.problematic)
	}
}

@(test)
mutable_local_reassignment_uses_runtime_storage :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-mutable"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/mutable_local", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 3)
}

@(test)
implicit_narrowing_produces_trap_executable :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-narrowing"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/narrowing_error", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
valid_runtime_global_initializes_before_main :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-runtime-global"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/runtime_global", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
inferred_string_global_decays_to_demanded_slice :: proc(t: ^testing.T) {
	text := "consume func(value []u8) usize { return value.len }\n" +
		"program ::\n\t`abc\n" +
		"main func() i32 {\n\tif consume(program) == 3 { return 0 }\n\treturn 1\n}\n"
	directory := "/tmp/brolang-test-inferred-string-global"
	main_path := "/tmp/brolang-test-inferred-string-global/main.bro"
	output := "/tmp/brolang-test-inferred-string-global-output"
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	testing.expect_value(t, compiler_core.compile_package(directory, output), 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
mutable_runtime_globals_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-mutable-global"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/mutable_global", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 52)
}

@(test)
mutable_globals_infer_constraints_and_emit_writable_storage :: proc(t: ^testing.T) {
	text := `Point :: struct {
	x i32
}
counter int = 0
ratio float = 1
span range = 0..2
point Point = Point { x = 1 }
values [_]mut i32 = [10, 20]
main func() void {
	counter = 1
	counter += 1
	point.x = counter
	values[1] = point.x
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	found_counter := false
	found_ratio := false
	found_span := false
	found_values := false
	for global in hir_module.globals {
		name := symbol.resolve(&symbols, global.name)
		if name == "counter" {
			found_counter = global.writable && !global.is_static && types.equal(global.type, types.I32)
		} else if name == "ratio" {
			found_ratio = global.writable && !global.is_static && types.equal(global.type, types.F64)
		} else if name == "span" {
			found_span = global.writable && !global.is_static && types.is_range(global.type, &hir_module.types)
		} else if name == "values" {
			item, ok := types.node(&hir_module.types, global.type)
			found_values = global.writable && !global.is_static && ok && item.kind == .Array && item.count == 2
		}
	}
	testing.expect(t, found_counter)
	testing.expect(t, found_ratio)
	testing.expect(t, found_span)
	testing.expect(t, found_values)
	testing.expect(t, strings.contains(llvm_text, "internal global"))
	testing.expect(t, !strings.contains(llvm_text, "internal constant i32 0"))
}

@(test)
mutable_global_diagnostics_and_no_shadowing :: proc(t: ^testing.T) {
	text := `ID :: distinct i32
OtherID :: distinct i32
ID i32 = 0
counter = 0
bad i32 = undefined
runtime i32 = 1
immutable :: 1
foo func(foo i32) void {}
main func() void {
	_ = $runtime
	immutable = 2
	OtherID i32 = 0
	local i32 = 0
	if true {
		local i32 = 1
	}
	for 0..1 |local| {}
	scope i32 = 0
	scope: {}
	mark: {
		mark i32 = 0
	}
	value i32 = value_label: {
		value_label i32 = 1
		yield :value_label 1
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	missing_type := false
	undefined_global := false
	not_comptime := false
	immutable_write := false
	global_type_shadow := false
	param_shadow := false
	local_type_shadow := false
	local_shadow := false
	capture_shadow := false
	label_shadow := false
	local_label_shadow := false
	value_label_shadow := false
	for diagnostic in diagnostics.items {
		missing_type = missing_type || strings.contains(diagnostic.message, "mutable global 'counter' requires a type annotation")
		undefined_global = undefined_global || strings.contains(diagnostic.message, "'undefined' is only valid as a mutable local declaration initializer")
		not_comptime = not_comptime || strings.contains(diagnostic.message, "global 'runtime' is not comptime-known")
		immutable_write = immutable_write || strings.contains(diagnostic.message, "assignment target is not writable")
		global_type_shadow = global_type_shadow || strings.contains(diagnostic.message, "global 'ID' shadows visible type")
		param_shadow = param_shadow || strings.contains(diagnostic.message, "parameter 'foo' shadows visible function")
		local_type_shadow = local_type_shadow || strings.contains(diagnostic.message, "local 'OtherID' shadows visible type")
		local_shadow = local_shadow || strings.contains(diagnostic.message, "local 'local' shadows visible local")
		capture_shadow = capture_shadow || strings.contains(diagnostic.message, "capture 'local' shadows visible local")
		label_shadow = label_shadow || strings.contains(diagnostic.message, "label 'scope' shadows visible local")
		local_label_shadow = local_label_shadow || strings.contains(diagnostic.message, "local 'mark' shadows visible label")
		value_label_shadow = value_label_shadow || strings.contains(diagnostic.message, "local 'value_label' shadows visible label")
	}
	testing.expect(t, missing_type)
	testing.expect(t, undefined_global)
	testing.expect(t, not_comptime)
	testing.expect(t, immutable_write)
	testing.expect(t, global_type_shadow)
	testing.expect(t, param_shadow)
	testing.expect(t, local_type_shadow)
	testing.expect(t, local_shadow)
	testing.expect(t, capture_shadow)
	testing.expect(t, label_shadow)
	testing.expect(t, local_label_shadow)
	testing.expect(t, value_label_shadow)
}

@(test)
unused_global_cycle_is_deferred :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-cycle-unused"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/cycle_unused", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
used_global_cycle_traps :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-cycle-used"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/cycle_used", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
malformed_typed_values_still_produce_executable :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-malformed-typed"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/malformed_typed_recovery", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
unused_invalid_function_body_is_not_checked :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-invalid-unused-function"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/invalid_unused_function", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
used_invalid_function_is_diagnosed_and_traps :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-invalid-used-function"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/invalid_used_function", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
function_mediated_problematic_global_is_deferred :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-function-global-unused"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/function_global_unused", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
function_mediated_problematic_global_traps_when_used :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-function-global-used"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/function_global_used", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
package_files_merge_and_qualified_imports_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-basic"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/basic/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 3)
}

@(test)
unused_import_is_diagnosed_but_remains_executable :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-unused"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/unused/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
unused_import_is_a_warning :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	module, loaded := loader.load("examples/packages/unused/app", &sources, &diagnostics, &symbols)
	defer ast.destroy_module(&module)
	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect(t, loaded)
	found := false
	for diagnostic, index in diagnostics.items {
		if strings.contains(diagnostic.message, "unused import 'math'") {
			found = true
			testing.expect_value(t, diagnostic.severity, source.Severity.Warning)
			formatted := source.format(&diagnostics, source.diagnostic_id(index))
			testing.expect(t, strings.contains(formatted, "warning: unused import 'math'"))
			delete(formatted)
		}
	}
	testing.expect(t, found)
}

@(test)
unused_missing_package_does_not_trap :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-missing-unused"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/missing_unused/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
referenced_missing_package_traps_at_reference :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-missing-used"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/missing_used/app", output)
	testing.expect_value(t, status, 1)
	state, stdout, stderr, _ := os2.process_exec(
		os2.Process_Desc{command=[]string{output}},
		context.allocator,
	)
	defer delete(stdout)
	defer delete(stderr)
	testing.expect(t, !state.success)
	testing.expect(t, strings.contains(string(stderr), "/missing_used/app/main.bro:4:6"))
}

@(test)
imports_are_file_local :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-file-local"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/file_local/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
hide_is_rejected_outside_named_top_level_declarations :: proc(t: ^testing.T) {
	cases := [?]string{
		`hide import "../dep"`,
		`hide dep :: import "../dep"`,
		`hide func() void {}`,
		`main func(hide value i32) void {}`,
		`Box :: struct { hide i32 }`,
		`main func() void { hide value i32 = 1 }`,
	}
	for text in cases {
		source_file := source.Source{path="test.bro", text=text}
		diagnostics := source.init_diagnostics(&source_file)
		defer source.destroy_diagnostics(&diagnostics)
		symbols := symbol.init_table()
		defer symbol.destroy_table(&symbols)
		stream := lexer.lex(&source_file, &diagnostics, &symbols)
		defer delete(stream.items)
		module := parser.parse(&stream, &source_file, &diagnostics)
		defer ast.destroy_module(&module)

		testing.expect(t, len(diagnostics.items) > 0)
	}
}

@(test)
hide_declarations_are_file_hidden :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-hidden-declarations"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/hidden_valid/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 9)
}

@(test)
file_hidden_declarations_are_not_package_members :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	module, loaded := loader.load("examples/packages/hidden_invalid/app", &sources, &diagnostics, &symbols)
	defer ast.destroy_module(&module)
	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect(t, loaded)
	found_sibling := false
	found_sibling_value := false
	found_sibling_type := false
	found_import := false
	found_collision := false
	for diagnostic in diagnostics.items {
		found_sibling = found_sibling || strings.contains(diagnostic.message, "unknown symbol 'sibling'")
		found_sibling_value = found_sibling_value || strings.contains(diagnostic.message, "unknown symbol 'sibling_value'")
		found_sibling_type = found_sibling_type || strings.contains(diagnostic.message, "unknown or opaque record type 'Sibling'")
		found_import = found_import || strings.contains(diagnostic.message, "package 'dep' has no member 'secret'")
		found_collision = found_collision || strings.contains(diagnostic.message, "duplicate function 'collision'")
	}
	testing.expect(t, found_sibling)
	testing.expect(t, found_sibling_value)
	testing.expect(t, found_sibling_type)
	testing.expect(t, found_import)
	testing.expect(t, found_collision)
}

@(test)
package_import_cycles_are_valid :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-cycle"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/cycle/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 4)
}

@(test)
imported_main_is_an_ordinary_callable_function :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-imported-main"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/imported_main/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 7)
}

@(test)
same_named_c_functions_in_packages_do_not_collide :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-c-symbols"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/c_symbols/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
invalid_root_package_preserves_existing_output :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-preserved-output"
	defer _ = os.remove(output)
	previous := "previous artifact"
	testing.expect(t, os.write_entire_file(output, transmute([]byte)previous))
	testing.expect_value(t, compiler_core.compile_package("examples/programs/prototype/main.bro", output), 2)
	data, ok := os.read_entire_file(output)
	defer delete(data)
	testing.expect(t, ok)
	testing.expect_value(t, string(data), previous)
}

@(test)
empty_root_package_is_an_infrastructure_error :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-empty"
	defer _ = os.remove(output)
	testing.expect_value(t, compiler_core.compile_package("examples/packages/empty", output), 2)
	testing.expect(t, !os.exists(output))
}

@(test)
same_package_can_be_imported_under_distinct_aliases :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-aliases"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/aliases/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 4)
}

@(test)
duplicate_same_file_import_keeps_first_binding :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-duplicate"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/duplicate/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 2)
}

@(test)
identical_imports_in_different_files_are_independent :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-repeated"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/repeated/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 4)
}

@(test)
imports_do_not_reexport_members :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-non-transitive"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/non_transitive/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
declaration_aliases_preserve_identity_and_chain :: proc(t: ^testing.T) {
	root :: "/tmp/brolang-test-declaration-aliases"
	dep_dir :: root + "/dep"
	facade_dir :: root + "/facade"
	top_dir :: root + "/top"
	app_dir :: root + "/app"
	output :: "/tmp/brolang-test-declaration-aliases-output"
	_ = os2.remove_all(root)
	defer _ = os2.remove_all(root)
	defer _ = os.remove(output)
	directories := [?]string{root, dep_dir, facade_dir, top_dir, app_dir}
	for directory in directories {
		testing.expect(t, os.make_directory(directory) == nil)
	}
	dep_text := `Box func($T type) type {
	return struct { value T }
}
Point :: struct { value i32 }
counter i32 = 1
answer func() i32 { return 40 }
`
	facade_text := `dep :: import "../dep"
RenamedBox :: alias dep.Box
RenamedPoint :: alias dep.Point
counter :: alias dep.counter
answer :: alias dep.answer
hide local_answer_alias :: alias dep.answer
local_answer func() i32 { return local_answer_alias() }
Scalar :: alias i32
MaybePoint :: alias ?@dep.Point
Concrete :: alias dep.Box(i32)
`
	top_text := `facade :: import "../facade"
Box :: alias facade.RenamedBox
Point :: alias facade.RenamedPoint
counter :: alias facade.counter
answer :: alias facade.answer
`
	app_text := `dep :: import "../dep"
facade :: import "../facade"
top :: import "../top"

main func() i32 {
	box top.Box(i32) :: top.Box(i32) { value = 2 }
	point top.Point :: top.Point { value = 3 }
	maybe facade.MaybePoint :: none
	scalar facade.Scalar :: 5
	top.counter = 7
	if box.value != 2 or point.value != 3 { return 1 }
	if scalar != 5 or top.answer() != 40 or facade.local_answer() != 40 or dep.counter != 7 { return 2 }
	_ = maybe
	return 0
}
`
	testing.expect(t, os.write_entire_file(dep_dir + "/dep.bro", transmute([]byte)dep_text))
	testing.expect(t, os.write_entire_file(facade_dir + "/facade.bro", transmute([]byte)facade_text))
	testing.expect(t, os.write_entire_file(top_dir + "/top.bro", transmute([]byte)top_text))
	testing.expect(t, os.write_entire_file(app_dir + "/main.bro", transmute([]byte)app_text))

	status := compiler_core.compile_package(app_dir, output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
declaration_aliases_diagnose_invalid_targets :: proc(t: ^testing.T) {
	root :: "/tmp/brolang-test-declaration-alias-errors"
	dep_dir :: root + "/dep"
	facade_dir :: root + "/facade"
	a_dir :: root + "/a"
	b_dir :: root + "/b"
	app_dir :: root + "/app"
	_ = os2.remove_all(root)
	defer _ = os2.remove_all(root)
	directories := [?]string{root, dep_dir, facade_dir, a_dir, b_dir, app_dir}
	for directory in directories {
		testing.expect(t, os.make_directory(directory) == nil)
	}
	dep_text := `visible func() i32 { return 1 }
hide hidden_target func() i32 { return 2 }
ambiguous func() i32 { return 3 }
ambiguous i32 :: 4
`
	facade_text := `dep :: import "../dep"
gone :: import "../gone"
missing :: alias dep.missing
hidden :: alias dep.hidden_target
unknown :: alias nope.visible
unavailable :: alias gone.visible
ambiguous :: alias dep.ambiguous
duplicate :: alias dep.visible
duplicate :: alias dep.visible
collision func() i32 { return 0 }
collision :: alias dep.visible
dep :: alias dep.visible
`
	a_text := `b :: import "../b"
value :: alias b.value
`
	b_text := `a :: import "../a"
value :: alias a.value
`
	app_text := `facade :: import "../facade"
a :: import "../a"
main func() void {}
`
	testing.expect(t, os.write_entire_file(dep_dir + "/dep.bro", transmute([]byte)dep_text))
	testing.expect(t, os.write_entire_file(facade_dir + "/facade.bro", transmute([]byte)facade_text))
	testing.expect(t, os.write_entire_file(a_dir + "/a.bro", transmute([]byte)a_text))
	testing.expect(t, os.write_entire_file(b_dir + "/b.bro", transmute([]byte)b_text))
	testing.expect(t, os.write_entire_file(app_dir + "/main.bro", transmute([]byte)app_text))

	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	module, loaded := loader.load(app_dir, &sources, &diagnostics, &symbols)
	defer ast.destroy_module(&module)
	testing.expect(t, loaded)
	wants := []string{
		"has no member 'missing'",
		"is file-hidden",
		"unknown symbol 'nope'",
		"unavailable imported package 'gone'",
		"package member 'dep.ambiguous' is ambiguous",
		"duplicate declaration alias 'duplicate'",
		"declaration alias 'collision' conflicts with a package declaration",
		"declaration alias 'dep' conflicts with an import",
		"declaration alias cycle",
	}
	for want in wants {
		found := false
		for diagnostic in diagnostics.items {
			found = found || strings.contains(diagnostic.message, want)
		}
		testing.expect(t, found)
	}
}

@(test)
self_import_via_dot_is_valid :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-self"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/self_import/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 5)
}

@(test)
unused_absolute_import_is_diagnosed_without_trapping :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-absolute"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/absolute/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
unreferenced_problematic_imported_global_is_deferred :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-problematic-unused"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/problematic_unused/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
valid_eager_global_in_unused_package_still_initializes :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-eager-unused"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/eager_unused/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
cross_package_global_initialization_cycle_traps_when_used :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-global-cycle"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/global_cycle/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
cross_package_generic_specializes_from_folded_argument :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-generic"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/generic/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 128)
}

@(test)
comptime_value_params_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-comptime-value-params"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/comptime_value_params", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
comptime_type_params_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-comptime-type-params"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/comptime_type_params", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
type_factories_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-type-factory"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/type_factory", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
arraylist_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-arraylist"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/arraylist", output, nil, target.DEFAULT, cimport.Options{}, ".")
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
type_factory_rejects_runtime_parameters_and_recursion :: proc(t: ^testing.T) {
	texts := []string{
		`Bad func($T type, n usize) type {
	return struct { value [n]T }
}
main func() void { value Bad(i32, 4) = undefined; _ = &value }
`,
		`Loop func($T type) type {
	return struct { next @Loop(T) }
}
main func() void { value Loop(i32) = undefined; _ = &value }
`,
		`Box func($T type) type {
	return struct { value T }
}
main func() void { _ = Box(i32) }
`,
		`Bad func($T type) type {
	return 1
}
main func() void { value Bad(i32) = undefined; _ = &value }
`,
	}
	wanted := []string{"must be comptime", "recursive type-factory specialization", "only valid in type position", "cannot implicitly convert"}
	for text, index in texts {
		source_file := source.Source{path="test.bro", text=text}
		diagnostics := source.init_diagnostics(&source_file)
		symbols := symbol.init_table()
		stream := lexer.lex(&source_file, &diagnostics, &symbols)
		ast_module := parser.parse(&stream, &source_file, &diagnostics)
		hir_module := checker.check(&ast_module, &diagnostics, &symbols)
		found := false
		for diagnostic in diagnostics.items {
			found = found || strings.contains(diagnostic.message, wanted[index])
		}
		testing.expect(t, found)
		hir.destroy_module(&hir_module)
		ast.destroy_module(&ast_module)
		delete(stream.items)
		symbol.destroy_table(&symbols)
		source.destroy_diagnostics(&diagnostics)
	}

}

@(test)
comptime_eval_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-comptime-eval"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/comptime_eval", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
comptime_v1_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-comptime-v1"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/comptime_v1", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
lazy_function_body_marks_import_as_used_without_resolving_it :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-lazy-import"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/lazy_import/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
qualified_global_inference_ignores_same_named_local :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-qualified-shadow"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/qualified_shadow/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 300)
}

@(test)
cross_package_recursive_specialization_reaches_fixed_point :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-recursive"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/recursive/app", output)
	testing.expect_value(t, status, 0)
	testing.expect(t, os.exists(output))
}

@(test)
imported_main_does_not_satisfy_root_main_requirement :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-missing-root-main"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/missing_root_main/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
package_llvm_is_deterministic_and_symbols_include_package_ids :: proc(t: ^testing.T) {
	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	ast_module, loaded := loader.load("examples/packages/c_symbols/app", &sources, &diagnostics, &symbols)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)
	second_llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(second_llvm_text)

	testing.expect(t, loaded)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, llvm_text, second_llvm_text)
	testing.expect(t, strings.contains(llvm_text, "define signext i8 @bro_c__p1__same"))
	testing.expect(t, strings.contains(llvm_text, "define signext i8 @bro_c__p2__same"))
	testing.expect(t, strings.contains(llvm_text, "define i32 @main()"))
}

@(test)
invalid_default_alias_requires_an_explicit_alias :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-default-alias-invalid"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/default_alias_invalid/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
explicit_alias_allows_invalid_directory_basename :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-explicit-alias"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/explicit_alias/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 3)
}

@(test)
import_alias_conflict_is_diagnosed_without_trapping :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-alias-conflict"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/alias_conflict/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 7)
}

@(test)
empty_imported_package_is_a_source_diagnostic :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-empty-import"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/empty_import/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
non_directory_import_is_a_source_diagnostic :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-file-import"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/file_import/app", output)
	testing.expect_value(t, status, 1)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
import_is_available_before_its_textual_declaration :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-import-order"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/import_order/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 6)
}

@(test)
deeply_nested_child_packages_load_recursively :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-package-deep"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/packages/deep/app", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 9)
}

@(test)
function_returning_only_in_if_branch_is_diagnosed :: proc(t: ^testing.T) {
	text := `classify func(n i32) i32 {
	if n > 0 {
		return 1
	}
}
main func() void {
	_ = classify(5)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "does not return a value")
	}
	testing.expect(t, found)
}

@(test)
function_returning_in_both_if_arms_is_accepted :: proc(t: ^testing.T) {
	text := `classify func(n i32) i32 {
	if n > 0 {
		return 1
	} else {
		return 0
	}
}
main func() void {
	_ = classify(5)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "does not return a value")
	}
	testing.expect(t, !found)
}

@(test)
function_returning_after_if_is_accepted :: proc(t: ^testing.T) {
	text := `classify func(n i32) i32 {
	if n > 0 {
		return 1
	}
	return 0
}
main func() void {
	_ = classify(5)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "does not return a value")
	}
	testing.expect(t, !found)
}

@(test)
conditional_unwrap_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-conditional-unwrap"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/conditional_unwrap", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	// Single unwrap, guarded two/three-value unwraps, optional pointers, false
	// guards, and failed short-circuit chains preserve the expected total.
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
conditional_unwrap_parser_captures_guard_and_parenthesized_chain :: proc(t: ^testing.T) {
	text := `main func() void {
	first ?i32 = 1
	second ?i32 = 2
	if (first and second) |a, b : a == 1 and b == 2| {
		_ = a
		_ = b
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	statement := module.statements[module.functions[0].body[2]]
	testing.expect_value(t, statement.kind, ast.Stmt_Kind.If)
	testing.expect_value(t, len(statement.captures), 2)
	testing.expect_value(t, module.exprs[statement.expr].kind, ast.Expr_Kind.And)
	testing.expect(t, module.exprs[statement.expr].parenthesized)
	testing.expect(t, statement.guard != ast.INVALID_EXPR)
	testing.expect_value(t, module.exprs[statement.guard].kind, ast.Expr_Kind.And)
}

@(test)
parser_accepts_braceless_if_bodies :: proc(t: ^testing.T) {
	text := `ready func() bool { return true }
main func() void {
	x i32 = 0
	if (x == 0) x = 1
	if ready() x = 2
	if (x == 2) x = 3 else x = 4
	if (x > 0) { x = 10 } else x = 11
	v ?i32 = 5
	if (v) |u| _ = u
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	main := module.functions[1]
	testing.expect_value(t, len(main.body), 7)

	paren_if := module.statements[main.body[1]]
	testing.expect_value(t, paren_if.kind, ast.Stmt_Kind.If)
	testing.expect_value(t, len(paren_if.body), 1)
	testing.expect(t, module.exprs[paren_if.expr].parenthesized)

	call_if := module.statements[main.body[2]]
	testing.expect_value(t, call_if.kind, ast.Stmt_Kind.If)
	testing.expect_value(t, len(call_if.body), 1)
	testing.expect_value(t, module.exprs[call_if.expr].kind, ast.Expr_Kind.Call)

	if_else := module.statements[main.body[3]]
	testing.expect_value(t, len(if_else.body), 1)
	testing.expect_value(t, len(if_else.else_body), 1)

	braced_then := module.statements[main.body[4]]
	testing.expect_value(t, len(braced_then.body), 1)
	testing.expect_value(t, len(braced_then.else_body), 1)

	unwrap_if := module.statements[main.body[6]]
	testing.expect_value(t, len(unwrap_if.captures), 1)
	testing.expect_value(t, len(unwrap_if.body), 1)
}

@(test)
parser_diagnoses_braceless_if_without_parens_or_call :: proc(t: ^testing.T) {
	text := `main func() void {
	x i32 = 0
	if x == 0 x = 1
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 1)
	testing.expect(t, strings.contains(diagnostics.items[0].message, "parenthesized"))
}

@(test)
parser_diagnoses_braceless_for_and_unwrap_without_parens_or_call :: proc(t: ^testing.T) {
	text := `main func() void {
	for tokens.items |item| _ = item
	value ?i32 = 1
	if value |present| _ = present
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 2)
	testing.expect(t, strings.contains(diagnostics.items[0].message, "brace-less 'for'"))
	testing.expect(t, strings.contains(diagnostics.items[1].message, "brace-less 'if'"))
}

@(test)
braceless_if_compiles_and_runs :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-braceless-if"
	main_path := "/tmp/brolang-test-braceless-if/main.bro"
	output := "/tmp/brolang-test-braceless-if-output"
	text := `ready func() bool { return true }
main func() i32 {
	x i32 = 0
	if (x == 0) x = 1 else x = 2
	if ready() x = x + 10
	y i32 = 5
	if (y == 0) y = 1 else y = 30
	x = x + y
	return x
}
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	status := compiler_core.compile_package(directory, output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 41)
}

@(test)
conditional_unwrap_allows_sink_captures :: proc(t: ^testing.T) {
	text := `main func() void {
	first ?i32 = 1
	second ?i32 = 2
	if first and second |_, value : value == 2| {
		_ = value
	}
	if first |_| {}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	main := hir_module.functions[0]
	first_if := hir_module.statements[main.body[2]]
	second_if := hir_module.statements[main.body[3]]
	testing.expect_value(t, first_if.unwraps[0].local, hir.INVALID_LOCAL)
	testing.expect(t, first_if.unwraps[1].local != hir.INVALID_LOCAL)
	testing.expect_value(t, second_if.unwraps[0].local, hir.INVALID_LOCAL)
}

@(test)
parser_diagnoses_malformed_conditional_unwrap_captures_and_guards :: proc(t: ^testing.T) {
	cases := [4]struct {
		text:   string,
		needle: string,
	}{
		{`main func() void {
	value ?i32 = 1
	if value || {}
}
`, "expected an unwrap capture name"},
		{`main func() void {
	value ?i32 = 1
	if value |capture,| {}
}
`, "expected an unwrap capture after ','"},
		{`main func() void {
	value ?i32 = 1
	if value |capture :| {}
}
`, "expected a guard expression after ':'"},
		{`main func() void {
	value ?i32 = 1
	if value |capture {}
}
`, "expected '|' to close unwrap captures"},
	}
	for test_case in cases {
		source_file := source.Source{path="test.bro", text=test_case.text}
		diagnostics := source.init_diagnostics(&source_file)
		symbols := symbol.init_table()
		stream := lexer.lex(&source_file, &diagnostics, &symbols)
		module := parser.parse(&stream, &source_file, &diagnostics)

		found := false
		for diagnostic in diagnostics.items {
			found = found || strings.contains(diagnostic.message, test_case.needle)
		}
		testing.expect(t, found)

		ast.destroy_module(&module)
		delete(stream.items)
		symbol.destroy_table(&symbols)
		source.destroy_diagnostics(&diagnostics)
	}

}

@(test)
if_unwrap_on_non_optional_is_diagnosed :: proc(t: ^testing.T) {
	text := `main func() i32 {
	x i32 = 5
	if x |v| {
		return v
	}
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "unwrap requires an optional")
	}
	testing.expect(t, found)
}

@(test)
conditional_unwrap_diagnostics_cover_counts_guards_and_capture_scope :: proc(t: ^testing.T) {
	text := `main func() void {
	first ?i32 = 1
	second ?i32 = 2
	plain i32 = 3

	if first and second |one| {}
	if first |one, two| {}
	if first and second |same, same| {}
	if plain |value| {}
	if first |value : value| {}
	if first and earlier |earlier, later| {}

	if first |value| {
		value = 2
	}
	if first |value| {
		value i32 = 2
		_ = value
	}
	if first |value| {
		_ = value
	} else {
		_ = value
	}
	_ = value
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	count_mismatches := 0
	duplicate := false
	non_optional := false
	guard := false
	outer_operand_scope := false
	immutable := false
	redeclaration := false
	capture_scope := 0
	for diagnostic in diagnostics.items {
		count_mismatches += 1 if strings.contains(diagnostic.message, "unwrap has") else 0
		duplicate = duplicate || strings.contains(diagnostic.message, "unwrap captures must have distinct names")
		non_optional = non_optional || strings.contains(diagnostic.message, "unwrap requires an optional value")
		guard = guard || strings.contains(diagnostic.message, "unwrap guard must be a bool")
		outer_operand_scope = outer_operand_scope || strings.contains(diagnostic.message, "unknown symbol 'earlier'")
		immutable = immutable || strings.contains(diagnostic.message, "cannot assign immutable local 'value'")
		redeclaration = redeclaration || strings.contains(diagnostic.message, "duplicate local 'value'")
		capture_scope += 1 if strings.contains(diagnostic.message, "unknown symbol 'value'") else 0
	}
	testing.expect_value(t, count_mismatches, 2)
	testing.expect(t, duplicate)
	testing.expect(t, non_optional)
	testing.expect(t, guard)
	testing.expect(t, outer_operand_scope)
	testing.expect(t, immutable)
	testing.expect(t, redeclaration)
	testing.expect_value(t, capture_scope, 2)
}

@(test)
if_unwrap_binding_is_scoped_to_then_block :: proc(t: ^testing.T) {
	// The binding `v` is usable in the then-block but not in the else-block.
	text := `main func() i32 {
	a ?i32 = 1
	if a |v| {
		return v
	} else {
		return v
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "unknown symbol 'v'")
	}
	testing.expect(t, found)
}

@(test)
if_unwrap_binding_is_immutable :: proc(t: ^testing.T) {
	text := `main func() i32 {
	a ?i32 = 1
	if a |v| {
		v = 2
		return v
	}
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "cannot assign immutable local 'v'")
	}
	testing.expect(t, found)
}

@(test)
while_loops_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-while-loop"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/while_loop", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
while_loop_diagnostics_cover_condition_update_and_scope :: proc(t: ^testing.T) {
	text := `bad_condition func() void {
	while 1 {}
}
bad_unresolved func() void {
	while false : missing = 1 {}
}
bad_immutable func() void {
	i :: 0
	while false : i = i + 1 {}
}
bad_body_scope func() void {
	running :: false
	while running : i = 1 {
		i u32 = 0
	}
}
bad_declaration_update func() void {
	while false : i u32 = 0 {}
}
bad_missing_update func() void {
	while false : {}
}
main func() void {
	bad_condition()
	bad_unresolved()
	bad_immutable()
	bad_body_scope()
	bad_declaration_update()
	bad_missing_update()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	non_bool := false
	unresolved_missing := false
	unresolved_body_local := false
	immutable := false
	disallowed := false
	missing := false
	for diagnostic in diagnostics.items {
		non_bool = non_bool || strings.contains(diagnostic.message, "'while' condition must be a bool")
		unresolved_missing = unresolved_missing || strings.contains(diagnostic.message, "cannot assign unresolved local 'missing'")
		unresolved_body_local = unresolved_body_local || strings.contains(diagnostic.message, "cannot assign unresolved local 'i'")
		immutable = immutable || strings.contains(diagnostic.message, "cannot assign immutable local 'i'")
		disallowed = disallowed || strings.contains(diagnostic.message, "while update must be an assignment, sink, or expression statement")
		missing = missing || strings.contains(diagnostic.message, "expected a while update statement after ':'")
	}
	testing.expect(t, non_bool)
	testing.expect(t, unresolved_missing)
	testing.expect(t, unresolved_body_local)
	testing.expect(t, immutable)
	testing.expect(t, disallowed)
	testing.expect(t, missing)
}

@(test)
while_true_and_potential_fallthrough_have_distinct_return_analysis :: proc(t: ^testing.T) {
	text := `forever func() i32 {
	while true {}
}
maybe func(run bool) i32 {
	while run {
		return 1
	}
}
main func() void {
	if false {
		_ = forever()
	}
	_ = maybe(false)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	missing_return_count := 0
	for diagnostic in diagnostics.items {
		if strings.contains(diagnostic.message, "does not return a value") {
			missing_return_count += 1
		}
	}
	testing.expect_value(t, missing_return_count, 1)
}

@(test)
while_loop_allocas_are_emitted_in_the_entry_block :: proc(t: ^testing.T) {
	text := `main func() i32 {
	i u32 = 0
	while i < 2 and true : i = i + 1 {
		value u32 = i
		_ = value
	}
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	first_loop_label := find_substring_offset(llvm_text, "bro_block_")
	testing.expect(t, first_loop_label >= 0)
	alloca_count := 0
	for function in ir_module.functions {
		if !function.is_main {
			continue
		}
		for instruction, instruction_index in function.instructions {
			if instruction.op != .Alloca {
				continue
			}
			alloca_count += 1
			needle := fmt.tprintf("  %%v%d = alloca ", instruction_index)
			offset := find_substring_offset(llvm_text, needle)
			testing.expect(t, offset >= 0 && offset < first_loop_label)
		}
	}
	testing.expect(t, alloca_count >= 3)
}

@(test)
for_loop_tokens_and_parser_capture_range_shape :: proc(t: ^testing.T) {
	text := `main func() void {
	for 0..4 |value| {
		_ = value
	}
	items [1]mut i32 = [1]
	for (&items) |@item, index| {
		_ = item
		_ = index
	}
	for 0..=1 |inclusive| {
		_ = inclusive
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)

	for_count := 0
	range_count := 0
	inclusive_count := 0
	for tok in stream.items {
		#partial switch tok.kind {
		case .Keyword_For:     for_count += 1
		case .Range:           range_count += 1
		case .Range_Inclusive: inclusive_count += 1
		case:
		}
	}
	testing.expect_value(t, for_count, 3)
	testing.expect_value(t, range_count, 1)
	testing.expect_value(t, inclusive_count, 1)

	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)
	testing.expect_value(t, len(diagnostics.items), 0)
	function := module.functions[0]
	first := module.statements[function.body[0]]
	second := module.statements[function.body[2]]
	third := module.statements[function.body[3]]
	testing.expect_value(t, first.kind, ast.Stmt_Kind.For)
	testing.expect(t, !first.pointer_capture)
	testing.expect_value(t, module.exprs[first.expr].kind, ast.Expr_Kind.Range)
	testing.expect_value(t, module.exprs[first.expr].integer, u64(0))
	testing.expect_value(t, second.kind, ast.Stmt_Kind.For)
	testing.expect(t, second.pointer_capture)
	testing.expect(t, symbol.is_valid(second.index_name))
	testing.expect_value(t, third.kind, ast.Stmt_Kind.For)
	testing.expect_value(t, module.exprs[third.expr].integer, u64(1))
}

@(test)
parser_accepts_braceless_for_bodies :: proc(t: ^testing.T) {
	text := `make_items func() [2]i32 { return [1, 2] }
main func() void {
	for (tokens.items) |item| _ = item
	for make_items() |item|
		_ = item
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	main := module.functions[1]
	testing.expect_value(t, len(main.body), 2)
	parenthesized := module.statements[main.body[0]]
	call := module.statements[main.body[1]]
	testing.expect_value(t, len(parenthesized.body), 1)
	testing.expect(t, module.exprs[parenthesized.expr].parenthesized)
	testing.expect_value(t, len(call.body), 1)
	testing.expect_value(t, module.exprs[call.expr].kind, ast.Expr_Kind.Call)
}

@(test)
braceless_for_compiles_and_runs :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-braceless-for"
	main_path := "/tmp/brolang-test-braceless-for/main.bro"
	output := "/tmp/brolang-test-braceless-for-output"
	text := `make_items func() [2]i32 { return [20, 2] }
main func() i32 {
	total i32 = 0
	items :: [10, 11]
	for (items) |item| total += item
	for make_items() |item|
		total += item
	return total
}
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	status := compiler_core.compile_package(directory, output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 43)
}

@(test)
range_bound_parenthesization_is_enforced :: proc(t: ^testing.T) {
	text := `main func() void {
	limit :: 3
	for 0..limit + 1 |bad| {
		_ = bad
	}
	for 0..(limit + 1) |good| {
		_ = good
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	found := 0
	for diagnostic in diagnostics.items {
		found += 1 if strings.contains(diagnostic.message, "range bounds with operators must be parenthesized") else 0
	}
	testing.expect_value(t, found, 1)
}

@(test)
parser_diagnoses_malformed_for_captures :: proc(t: ^testing.T) {
	cases := [4]struct {
		text:   string,
		needle: string,
	}{
		{`main func() void {
	for [1] item {}
}
`, "expected '|' before for-loop captures"},
		{`main func() void {
	for [1] |@| {}
}
`, "expected a for-loop item capture"},
		{`main func() void {
	for [1] |item,| {}
}
`, "expected an index capture after ','"},
		{`main func() void {
	for [1] |item {}
}
`, "expected '|' to close for-loop captures"},
	}
	for test_case in cases {
		source_file := source.Source{path="test.bro", text=test_case.text}
		diagnostics := source.init_diagnostics(&source_file)
		symbols := symbol.init_table()
		stream := lexer.lex(&source_file, &diagnostics, &symbols)
		module := parser.parse(&stream, &source_file, &diagnostics)

		found := false
		for diagnostic in diagnostics.items {
			found = found || strings.contains(diagnostic.message, test_case.needle)
		}
		testing.expect(t, found)

		ast.destroy_module(&module)
		delete(stream.items)
		symbol.destroy_table(&symbols)
		source.destroy_diagnostics(&diagnostics)
	}
}

@(test)
for_loops_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-for-loop"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/for_loop", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
range_loop_edges_compile_and_run :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-for-loop-edges"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/for_loop_edges", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
for_loop_diagnostics_cover_iterables_captures_and_scope :: proc(t: ^testing.T) {
	text := `bad_iterable func() void {
	for 1 |item| {
		_ = item
	}
}
bad_array_pointer_capture func() void {
	for [1] |@item| {
		_ = item
	}
}
bad_range_pointer_capture func() void {
	for 0..1 |@item| {
		_ = item
	}
}
bad_range_index_capture func() void {
	for 0..1 |item, index| {
		_ = item
		_ = index
	}
}
bad_duplicate_capture func() void {
	for [1] |item, item| {
		_ = item
	}
}
bad_capture_redeclaration func() void {
	for [1] |item| {
		item i32 = 2
		_ = item
	}
}
bad_capture_assignment func() void {
	for [1] |item| {
		item = 2
	}
}
bad_immutable_pointer_capture func() void {
	items :: [1]
	for (&items) |@item| {
		item^ = 2
	}
}
bad_scope func() void {
	for [1] |item| {
		_ = item
	}
	_ = item
}
bad_integer_bounds func() void {
	start i32 = 0
	end u32 = 1
	for start..end |item| {
		_ = item
	}
}
bad_float_bounds func() void {
	for 0.0..1.0 |item| {
		_ = item
	}
}
main func() void {
	bad_iterable()
	bad_array_pointer_capture()
	bad_range_pointer_capture()
	bad_range_index_capture()
	bad_duplicate_capture()
	bad_capture_redeclaration()
	bad_capture_assignment()
	bad_immutable_pointer_capture()
	bad_scope()
	bad_integer_bounds()
	bad_float_bounds()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	unsupported := false
	array_pointer := false
	range_pointer := false
	range_index := false
	duplicate_capture := false
	redeclaration := false
	immutable := false
	immutable_pointer := false
	scope := false
	integer_bounds := 0
	for diagnostic in diagnostics.items {
		unsupported = unsupported || strings.contains(diagnostic.message, "for-loop iterable must be a range")
		array_pointer = array_pointer || strings.contains(diagnostic.message, "pointer capture over an array requires")
		range_pointer = range_pointer || strings.contains(diagnostic.message, "range loops do not support pointer captures")
		range_index = range_index || strings.contains(diagnostic.message, "range loops do not support index captures")
		duplicate_capture = duplicate_capture || strings.contains(diagnostic.message, "for-loop captures must have distinct names")
		redeclaration = redeclaration || strings.contains(diagnostic.message, "duplicate local 'item'")
		immutable = immutable || strings.contains(diagnostic.message, "cannot assign immutable local 'item'")
		immutable_pointer = immutable_pointer || strings.contains(diagnostic.message, "assignment target is not writable")
		scope = scope || strings.contains(diagnostic.message, "unknown symbol 'item'")
		integer_bounds += 1 if strings.contains(diagnostic.message, "range bounds must be compatible concrete integers") else 0
	}
	testing.expect(t, unsupported)
	testing.expect(t, array_pointer)
	testing.expect(t, range_pointer)
	testing.expect(t, range_index)
	testing.expect(t, duplicate_capture)
	testing.expect(t, redeclaration)
	testing.expect(t, immutable)
	testing.expect(t, immutable_pointer)
	testing.expect(t, scope)
	testing.expect_value(t, integer_bounds, 2)
}

@(test)
for_pointer_capture_respects_pointer_and_array_mutability :: proc(t: ^testing.T) {
	text := `readonly func() void {
	values [1]mut i32 = [1]
	items @[1]mut i32 = &values
	items[0] = 7
	for items |@item| {
		item^ = 7
	}
}
writable func() void {
	values [1]mut i32 = [1]
	items @mut [1]mut i32 = &values
	items[0] = 7
	for items |@item| {
		item^ = 7
	}
}
main func() void {
	readonly()
	writable()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	readonly_errors := 0
	for diagnostic in diagnostics.items {
		readonly_errors += 1 if strings.contains(diagnostic.message, "assignment target is not writable") else 0
	}
	testing.expect_value(t, readonly_errors, 2)
}

@(test)
pointer_field_passthrough_respects_pointee_mutability :: proc(t: ^testing.T) {
	text := `Point :: struct {
	x i32
}
readonly func(point @Point) i32 {
	return point.x
}
bad_write func(point @Point) void {
	point.x = 7
}
writable func(point @mut Point) void {
	point.x += 1
}
main func() i32 {
	point Point = Point { x = 41 }
	writable(&point)
	bad_write(&point)
	return readonly(&point)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	readonly_errors := 0
	for diagnostic in diagnostics.items {
		readonly_errors += 1 if strings.contains(diagnostic.message, "assignment target is not writable") else 0
	}
	testing.expect_value(t, readonly_errors, 1)
}

@(test)
equal_range_returns_infer_a_usable_result_type :: proc(t: ^testing.T) {
	text := `choose func(first bool) range {
	if first {
		return 0..1
	}
	return 2..3
}
main func() i32 {
	total i32 = 0
	for choose(false) |value| {
		total = total + value
	}
	return total
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	found := false
	for function in hir_module.functions {
		if symbol.resolve(&symbols, function.name) == "choose" {
			found = true
			testing.expect(t, types.is_range(function.result, &hir_module.types))
			testing.expect_value(t, types.child_type(function.result, &hir_module.types), types.I8)
		}
	}
	testing.expect(t, found)
	testing.expect(t, strings.contains(llvm_text, "extractvalue"))
}

@(test)
for_loop_lowering_evaluates_once_and_avoids_index_bounds_checks :: proc(t: ^testing.T) {
	text := `make_range func() range {
	return 0..2
}
make_array func() [2]i32 {
	return [1, 2]
}
main func() i32 {
	total i32 = 0
	for make_range() |value| {
		total = total + value
	}
	for make_array() |value| {
		total = total + value
	}
	return total
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	call_count := 0
	extract_count := 0
	select_count := 0
	pointer_add_count := 0
	index_address_count := 0
	first_loop_label := find_substring_offset(llvm_text, "bro_block_")
	testing.expect(t, first_loop_label >= 0)
	for function in ir_module.functions {
		if !function.is_main {
			continue
		}
		for instruction, instruction_index in function.instructions {
			#partial switch instruction.op {
			case .Call:          call_count += 1
			case .Extract:       extract_count += 1
			case .Select:        select_count += 1
			case .Pointer_Add:   pointer_add_count += 1
			case .Index_Address: index_address_count += 1
			case .Alloca:
				needle := fmt.tprintf("  %%v%d = alloca ", instruction_index)
				offset := find_substring_offset(llvm_text, needle)
				testing.expect(t, offset >= 0 && offset < first_loop_label)
			case:
			}
		}
	}
	testing.expect_value(t, call_count, 2)
	testing.expect_value(t, extract_count, 3)
	testing.expect_value(t, select_count, 2)
	testing.expect(t, pointer_add_count >= 1)
	testing.expect_value(t, index_address_count, 0)
	testing.expect(t, !strings.contains(llvm_text, "index_ok"))
}

@(test)
lexer_emits_compound_assignment_and_slash_tokens :: proc(t: ^testing.T) {
	source_file := source.Source{path="test.bro", text="+= -= *= /= / *"}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, stream.items[0].kind, token.Kind.Plus_Equal)
	testing.expect_value(t, stream.items[1].kind, token.Kind.Minus_Equal)
	testing.expect_value(t, stream.items[2].kind, token.Kind.Star_Equal)
	testing.expect_value(t, stream.items[3].kind, token.Kind.Slash_Equal)
	testing.expect_value(t, stream.items[4].kind, token.Kind.Slash)
	testing.expect_value(t, stream.items[5].kind, token.Kind.Star)
}

@(test)
binary_operators_respect_multiplicative_precedence :: proc(t: ^testing.T) {
	source_file := source.Source{path="test.bro", text="value :: 1 + 2 * 3\nmain func() void {}\n"}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	root := module.exprs[module.globals[0].expr]
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, root.kind, ast.Expr_Kind.Add)
	testing.expect_value(t, module.exprs[root.left].integer, u64(1))
	testing.expect_value(t, module.exprs[root.right].kind, ast.Expr_Kind.Mul)
}

@(test)
division_parses_left_associatively :: proc(t: ^testing.T) {
	source_file := source.Source{path="test.bro", text="value :: 8 / 4 / 2\nmain func() void {}\n"}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	root := module.exprs[module.globals[0].expr]
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, root.kind, ast.Expr_Kind.Div)
	testing.expect_value(t, module.exprs[root.left].kind, ast.Expr_Kind.Div)
	testing.expect_value(t, module.exprs[root.right].integer, u64(2))
}

@(test)
compound_assignment_preserves_operation_and_rhs :: proc(t: ^testing.T) {
	text := `main func() void {
	x i32 = 0
	x += 5
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	body := module.functions[0].body
	statement := module.statements[body[1]]
	testing.expect_value(t, statement.kind, ast.Stmt_Kind.Assignment)
	testing.expect_value(t, statement.assignment_op, ast.Assignment_Op.Add)
	testing.expect(t, statement.target != ast.INVALID_EXPR)
	testing.expect_value(t, module.exprs[statement.target].kind, ast.Expr_Kind.Name)
	testing.expect_value(t, module.exprs[statement.expr].kind, ast.Expr_Kind.Integer)
	testing.expect_value(t, module.exprs[statement.expr].integer, u64(5))
}

@(test)
undefined_inferred_local_lowers_to_fill :: proc(t: ^testing.T) {
	text := `choose func(flag bool) i32 {
	value int = undefined
	if flag {
		value = 42
	} else {
		value = -2
	}
	return value
}
main func() i32 {
	return choose(true)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	choose_symbol := symbol.intern(&symbols, "choose")
	value_symbol := symbol.intern(&symbols, "value")
	found_value_i32 := false
	fill_count := 0
	for function, function_index in hir_module.functions {
		if function.name != choose_symbol {
			continue
		}
		for local in function.locals {
			found_value_i32 = found_value_i32 || local.name == value_symbol && local.type == types.I32
		}
		for instruction in ir_module.functions[function_index].instructions {
			fill_count += 1 if instruction.op == .Fill else 0
		}
	}

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found_value_i32)
	testing.expect_value(t, fill_count, 1)
	testing.expect(t, strings.contains(llvm_text, "declare void @llvm.memset.p0.i64"))
	testing.expect(t, strings.contains(llvm_text, "call void @llvm.memset.p0.i64"))
	testing.expect(t, strings.contains(llvm_text, "i8 -86"))
}

@(test)
local_int_inference_widens_from_assignments :: proc(t: ^testing.T) {
	text := `wide func() int {
	value int = 1
	value = 1000
	return value
}
main func() void {
	_ = wide()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	wide_symbol := symbol.intern(&symbols, "wide")
	value_symbol := symbol.intern(&symbols, "value")
	found_value_i16 := false
	found_result_i16 := false
	for function in hir_module.functions {
		if function.name != wide_symbol {
			continue
		}
		found_result_i16 = function.result == types.I16
		for local in function.locals {
			found_value_i16 = found_value_i16 || local.name == value_symbol && local.type == types.I16
		}
	}

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found_result_i16)
	testing.expect(t, found_value_i16)
}

float_local_type :: proc(hir_module: ^hir.Module, symbols: ^symbol.Table, function_name, local_name: string) -> (types.Type, bool) {
	fn_symbol := symbol.intern(symbols, function_name)
	loc_symbol := symbol.intern(symbols, local_name)
	for function in hir_module.functions {
		if function.name != fn_symbol {
			continue
		}
		for local in function.locals {
			if local.name == loc_symbol {
				return local.type, true
			}
		}
	}
	return types.INVALID, false
}

float_result_type :: proc(hir_module: ^hir.Module, symbols: ^symbol.Table, function_name: string) -> (types.Type, bool) {
	fn_symbol := symbol.intern(symbols, function_name)
	for function in hir_module.functions {
		if function.name == fn_symbol {
			return function.result, true
		}
	}
	return types.INVALID, false
}

@(test)
float_constraint_resolves_to_f64 :: proc(t: ^testing.T) {
	text := `make func() float {
	pi float = 3.14
	return pi
}
main func() void {
	_ = make()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	pi_type, found := float_local_type(&hir_module, &symbols, "make", "pi")
	result_type, _ := float_result_type(&hir_module, &symbols, "make")

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found)
	testing.expect_value(t, pi_type, types.F64)
	testing.expect_value(t, result_type, types.F64)
}

@(test)
float_constraint_accepts_integer_literal :: proc(t: ^testing.T) {
	text := `make func() float {
	pi float = 3
	return pi
}
main func() void {
	_ = make()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	pi_type, found := float_local_type(&hir_module, &symbols, "make", "pi")

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found)
	testing.expect_value(t, pi_type, types.F64)
}

@(test)
float_constraint_result_resolves_to_f64 :: proc(t: ^testing.T) {
	text := `make func() float {
	return 3.0
}
main func() void {
	_ = make()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	result_type, found := float_result_type(&hir_module, &symbols, "make")

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found)
	testing.expect_value(t, result_type, types.F64)
}

@(test)
float_constraint_widens_f32_to_f64 :: proc(t: ^testing.T) {
	text := `wide func(a f32, b f64) float {
	x float = a
	x = b
	return x
}
main func() void {
	_ = wide(1.0, 2.0)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	x_type, found := float_local_type(&hir_module, &symbols, "wide", "x")
	result_type, _ := float_result_type(&hir_module, &symbols, "wide")

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found)
	testing.expect_value(t, x_type, types.F64)
	testing.expect_value(t, result_type, types.F64)
}

@(test)
int_constraint_rejects_float_initializer :: proc(t: ^testing.T) {
	text := `main func() void {
	x int = 1.0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_constraint_error := false
	for diagnostic in diagnostics.items {
		found_constraint_error = found_constraint_error ||
			strings.contains(diagnostic.message, "could not resolve the 'int' constraint for local 'x'")
	}

	testing.expect(t, found_constraint_error)
}

@(test)
float_constraint_rejects_runtime_integer :: proc(t: ^testing.T) {
	text := `take func(n i32) void {
	x float = n
}
main func() void {
	take(7)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_convert_error := false
	for diagnostic in diagnostics.items {
		found_convert_error = found_convert_error ||
			strings.contains(diagnostic.message, "cannot implicitly convert i32 to f64")
	}

	testing.expect(t, found_convert_error)
}

@(test)
range_constraint_local_resolves_to_inferred_range :: proc(t: ^testing.T) {
	text := `make func() range {
	r range :: 0..10
	return r
}
main func() void {
	_ = make()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	r_type, found := float_local_type(&hir_module, &symbols, "make", "r")
	result_type, _ := float_result_type(&hir_module, &symbols, "make")

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found)
	testing.expect(t, types.is_range(r_type, &hir_module.types))
	testing.expect_value(t, types.child_type(r_type, &hir_module.types), types.I8)
	testing.expect(t, types.is_range(result_type, &hir_module.types))
}

@(test)
range_constraint_param_and_result_monomorphize :: proc(t: ^testing.T) {
	text := `pass func(r range) range {
	return r
}
main func() void {
	once :: 0..5
	for pass(once) |v| {
		_ = v
	}
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	result_type, found := float_result_type(&hir_module, &symbols, "pass")

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found)
	testing.expect(t, types.is_range(result_type, &hir_module.types))
}

@(test)
int_param_rejects_float_argument :: proc(t: ^testing.T) {
	text := `take func(x int) int {
	return x
}
main func() void {
	_ = take(1.5)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_reject := false
	for diagnostic in diagnostics.items {
		found_reject = found_reject ||
			strings.contains(diagnostic.message, "cannot pass f64 to 'int' parameter 'x'")
	}

	testing.expect(t, found_reject)
}

@(test)
float_param_accepts_integer_literal_argument :: proc(t: ^testing.T) {
	text := `take func(x float) float {
	return x
}
main func() void {
	y f64 = take(3)
	_ = y
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	result_type, found := float_result_type(&hir_module, &symbols, "take")

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, found)
	testing.expect_value(t, result_type, types.F64)
}

@(test)
undefined_accepts_concrete_runtime_annotations :: proc(t: ^testing.T) {
	text := `Point :: struct {
	x i32
	y i32
}
main func() void {
	point Point = undefined
	pointer @i32 = undefined
	maybe ?i32 = undefined
	_ = point
	_ = pointer
	_ = maybe
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)

	main_symbol := symbol.intern(&symbols, "main")
	fill_count := 0
	for function, function_index in hir_module.functions {
		if function.name != main_symbol {
			continue
		}
		for instruction in ir_module.functions[function_index].instructions {
			fill_count += 1 if instruction.op == .Fill else 0
		}
	}

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, fill_count, 3)
}

@(test)
undefined_rejects_non_declaration_uses_and_unresolved_inference :: proc(t: ^testing.T) {
	text := `global :: undefined
main func() void {
	immutable :: undefined
	typed_immutable int :: undefined
	unresolved int = undefined
	existing i32 = 1
	existing = undefined
	mismatch int = undefined
	mismatch = 1
	mismatch = 1.0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	immutable_count := 0
	found_unresolved := false
	found_assignment := false
	found_incompatible := false
	for diagnostic in diagnostics.items {
		immutable_count += 1 if strings.contains(diagnostic.message, "'undefined' requires a mutable local declaration") else 0
		found_unresolved = found_unresolved || strings.contains(diagnostic.message, "could not infer a concrete type for local 'unresolved'")
		found_assignment = found_assignment || strings.contains(diagnostic.message, "'undefined' is only valid as a mutable local declaration initializer")
		found_incompatible = found_incompatible || strings.contains(diagnostic.message, "cannot implicitly convert f64 to i8")
	}

	testing.expect(t, immutable_count >= 2)
	testing.expect(t, found_unresolved)
	testing.expect(t, found_assignment)
	testing.expect(t, found_incompatible)
}

@(test)
compound_assignment_evaluates_lvalue_once :: proc(t: ^testing.T) {
	// A compound assignment to an indexed lvalue must compute the element address
	// once and reuse it for the load and the store, rather than re-lowering the
	// lvalue (which would re-evaluate any side-effecting index subexpression).
	text := `bump func() usize {
	return 1
}
main func() i32 {
	values [3]mut i32 = [10, 20, 30]
	values[bump()] += 5
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	call_count := 0
	index_address_count := 0
	for function in ir_module.functions {
		if !function.is_main {
			continue
		}
		for instruction in function.instructions {
			#partial switch instruction.op {
			case .Call:          call_count += 1
			case .Index_Address: index_address_count += 1
			case:
			}
		}
	}
	// `bump()` is the lvalue's index. The fix shares one address between the load
	// and the store, so the side-effecting index runs exactly once and a single
	// Index_Address is emitted; the buggy double-lowering produced two of each.
	testing.expect_value(t, call_count, 1)
	testing.expect_value(t, index_address_count, 1)
}

@(test)
compound_assignment_evaluates_nested_locations_once :: proc(t: ^testing.T) {
	text := `Box :: struct {
	value i32
}
row func() usize {
	return 0
}
column func() usize {
	return 1
}
pointer_for func(value @mut i32) @mut i32 {
	return value
}
main func() i32 {
	matrix [2]mut [2]mut i32 = [[1, 2], [3, 4]]
	(matrix[row()])[column()] += 1
	boxes [2]mut Box = [Box { value = 5 }, Box { value = 6 }]
	boxes[row()].value += 1
	value i32 = 7
	pointer_for(&value)^ += 1
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)

	testing.expect_value(t, len(diagnostics.items), 0)
	call_count := 0
	call_names: [4]string
	index_address_count := 0
	field_address_count := 0
	for function in ir_module.functions {
		if !function.is_main {
			continue
		}
		for instruction in function.instructions {
			#partial switch instruction.op {
			case .Call:
				function_id := ir.as_function(instruction.target)
				if call_count < len(call_names) &&
				   function_id != ir.INVALID_FUNCTION &&
				   int(function_id) < len(hir_module.functions) {
					call_names[call_count] = symbol.resolve(
						&symbols,
						hir_module.functions[function_id].name,
					)
				}
				call_count += 1
			case .Index_Address: index_address_count += 1
			case .Field_Address: field_address_count += 1
			case:
			}
		}
	}
	// row(), column(), the second row(), and pointer_for() each run once. The
	// nested matrix target needs two index addresses; the indexed field needs
	// one index address and one field address.
	testing.expect_value(t, call_count, 4)
	testing.expect_value(t, call_names, [4]string{"row", "column", "row", "pointer_for"})
	testing.expect_value(t, index_address_count, 3)
	testing.expect_value(t, field_address_count, 1)
}

@(test)
compound_assignment_supports_pointer_add_only :: proc(t: ^testing.T) {
	valid_text := `main func() i32 {
	values [3]mut i32 = [10, 20, 30]
	pointer *mut i32 = (&values).ptr
	pointer += 1
	offset usize = 1
	pointer += offset
	return pointer^
}
`
	source_file := source.Source{path="test.bro", text=valid_text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)

	pointer_add_count := 0
	for function in ir_module.functions {
		if !function.is_main {
			continue
		}
		for instruction in function.instructions {
			pointer_add_count += 1 if instruction.op == .Pointer_Add else 0
		}
	}
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, pointer_add_count, 2)

	invalid_text := `main func() void {
	values [1]mut i32 = [10]
	pointer *mut i32 = (&values).ptr
	pointer -= 1
}
`
	invalid_source := source.Source{path="invalid.bro", text=invalid_text}
	invalid_diagnostics := source.init_diagnostics(&invalid_source)
	defer source.destroy_diagnostics(&invalid_diagnostics)
	invalid_symbols := symbol.init_table()
	defer symbol.destroy_table(&invalid_symbols)
	invalid_stream := lexer.lex(&invalid_source, &invalid_diagnostics, &invalid_symbols)
	defer delete(invalid_stream.items)
	invalid_ast := parser.parse(&invalid_stream, &invalid_source, &invalid_diagnostics)
	defer ast.destroy_module(&invalid_ast)
	invalid_hir := checker.check(&invalid_ast, &invalid_diagnostics, &invalid_symbols)
	defer hir.destroy_module(&invalid_hir)

	found := false
	for diagnostic in invalid_diagnostics.items {
		found = found || strings.contains(
			diagnostic.message,
			"many-item pointers only support '+=' compound assignment",
		)
	}
	testing.expect(t, found)
}

@(test)
compound_assignment_preserves_checked_numeric_operations :: proc(t: ^testing.T) {
	text := `main func() i32 {
	signed i32 = 24
	signed += 6
	signed -= 2
	signed *= 3
	signed = divtrunc!(signed, 4)
	unsigned u32 = 24
	unsigned += 6
	unsigned -= 2
	unsigned *= 3
	unsigned = divtrunc!(unsigned, 4)
	real f64 = 24.0
	real += 6.0
	real -= 2.0
	real *= 3.0
	real /= 4.0
	return signed
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)

	operation_counts: [hir.Assignment_Op]int
	for statement_id in hir_module.functions[0].body {
		statement := hir_module.statements[statement_id]
		if statement.kind == .Assignment {
			operation_counts[statement.assignment_op] += 1
		}
	}
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, operation_counts[.Add], 3)
	testing.expect_value(t, operation_counts[.Sub], 3)
	testing.expect_value(t, operation_counts[.Mul], 3)
	testing.expect_value(t, operation_counts[.Div], 1)

	add_count := 0
	sub_count := 0
	mul_count := 0
	div_count := 0
	div_trunc_count := 0
	for instruction in ir_module.functions[0].instructions {
		#partial switch instruction.op {
		case .Add_Checked: add_count += 1
		case .Sub_Checked: sub_count += 1
		case .Mul_Checked: mul_count += 1
		case .Div_Checked: div_count += 1
		case .Div_Trunc_Checked: div_trunc_count += 1
		case:
		}
	}
	testing.expect_value(t, add_count, 3)
	testing.expect_value(t, sub_count, 3)
	testing.expect_value(t, mul_count, 3)
	testing.expect_value(t, div_count, 1)
	testing.expect_value(t, div_trunc_count, 2)
}

@(test)
compound_assignment_rejects_narrowing_and_mixed_numeric_families :: proc(t: ^testing.T) {
	text := `main func() void {
	narrow i8 = 1
	wide i32 = 2
	narrow += wide
	signed i32 = 3
	unsigned u32 = 4
	signed += unsigned
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_narrowing := false
	found_mixed_family := false
	for diagnostic in diagnostics.items {
		found_narrowing = found_narrowing ||
		                  strings.contains(diagnostic.message, "cannot implicitly convert i32 to i8")
		found_mixed_family = found_mixed_family ||
		                     strings.contains(diagnostic.message, "arithmetic requires compatible numeric operands")
	}
	testing.expect(t, found_narrowing)
	testing.expect(t, found_mixed_family)
}

@(test)
compound_assignment_compiles_and_runs :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-compound"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/compound_assignment", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 23)
}

@(test)
binary_arithmetic_rejects_non_numeric_operands :: proc(t: ^testing.T) {
	text := `main func() i32 {
	a i32 = 1
	b u32 = 2
	_ = a + b
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "arithmetic requires compatible numeric operands")
	}
	testing.expect(t, found)
}

@(test)
compound_assignment_requires_writable_target :: proc(t: ^testing.T) {
	text := `main func() i32 {
	x :: 5
	x += 1
	return x
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "assignment target is not writable")
	}
	testing.expect(t, found)
}

@(test)
checked_division_and_subtraction_emit_guarded_llvm :: proc(t: ^testing.T) {
	text := `main func() i32 {
	a i32 = 10
	b i32 = 3
	c i32 = a - b
	return divtrunc!(c, b)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, strings.contains(llvm_text, "@llvm.ssub.with.overflow.i32"))
	testing.expect(t, strings.contains(llvm_text, "sdiv i32"))
	testing.expect(t, strings.contains(llvm_text, "divzero_trap"))
	testing.expect(t, strings.contains(llvm_text, "divovf_trap"))
}

@(test)
integer_slash_is_rejected_and_float_slash_remains_available :: proc(t: ^testing.T) {
	Case :: struct {text, want: string}
	invalid := []Case{
		{text=`main func() void {
	a i32 = 4
	b i32 = 2
	_ = a / b
}`, want="integer '/' is not allowed"},
		{text=`main func() void {
	a u32 = 4
	b u32 = 2
	_ = a / b
}`, want="integer '/' is not allowed"},
		{text=`main func() void {
	_ = 4 / 2
}`, want="integer '/' is not allowed"},
		{text=`main func() void {
	values [4 / 2]u8 = undefined
	_ = &values
}`, want="integer '/' is not allowed"},
		{text=`half func($value i32) i32 { return value / 2 }
main func() void { _ = $half(4) }`, want="integer '/' is not allowed"},
		{text=`main func() void {
	value i32 = 8
	value /= 2
}`, want="assign through an explicit division builtin"},
	}
	for test_case in invalid {
		source_file := source.Source{path="test.bro", text=test_case.text}
		diagnostics := source.init_diagnostics(&source_file)
		symbols := symbol.init_table()
		stream := lexer.lex(&source_file, &diagnostics, &symbols)
		ast_module := parser.parse(&stream, &source_file, &diagnostics)
		hir_module := checker.check(&ast_module, &diagnostics, &symbols)
		found := false
		for diagnostic in diagnostics.items {
			found = found || strings.contains(diagnostic.message, test_case.want)
		}
		testing.expect(t, found)
		hir.destroy_module(&hir_module)
		ast.destroy_module(&ast_module)
		delete(stream.items)
		symbol.destroy_table(&symbols)
		source.destroy_diagnostics(&diagnostics)
	}

	text := `main func() void {
	value f32 = 5.0 / 2.0
	value /= 2.0
	_ = value
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
division_builtins_diagnose_arity_operands_and_comptime_failures :: proc(t: ^testing.T) {
	text := `bad_arity :: divfloor!(1)
bad_bool :: rem!(true, false)
bad_family :: mod!(i32(5), f32(3))
zero_trunc :: divtrunc!(1, 0)
zero_floor :: divfloor!(1.0, 0.0)
zero_exact :: divexact!(1, 0)
zero_ceil :: divceil!(1.0, 0.0)
zero_rem :: rem!(1, 0)
zero_mod :: mod!(1.0, 0.0)
inexact :: divexact!(5, 3)
overflow_trunc :: divtrunc!(minval!(i32), -1)
overflow_floor :: divfloor!(minval!(i32), -1)
overflow_exact :: divexact!(minval!(i32), -1)
overflow_ceil :: divceil!(minval!(i32), -1)
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	zero_count := 0
	found_arity, found_operands, found_exact := false, false, false
	overflow_count := 0
	for diagnostic in diagnostics.items {
		found_arity = found_arity || strings.contains(diagnostic.message, "expects 2 arguments")
		found_operands = found_operands || strings.contains(diagnostic.message, "compatible numeric operands")
		found_exact = found_exact || strings.contains(diagnostic.message, "exact division has a remainder")
		if strings.contains(diagnostic.message, "signed integer division overflow") {
			overflow_count += 1
		}
		if strings.contains(diagnostic.message, "division builtin denominator is zero") {
			zero_count += 1
		}
	}
	testing.expect(t, found_arity)
	testing.expect(t, found_operands)
	testing.expect(t, found_exact)
	testing.expect_value(t, overflow_count, 4)
	testing.expect_value(t, zero_count, 6)
}

@(test)
division_family_compiles_and_runs_for_integer_and_float_scalars :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-division-family"
	main_path := "/tmp/brolang-test-division-family/main.bro"
	output := "/tmp/brolang-test-division-family-output"
	text := `COUNT :: divexact!(8, 2)
items [divceil!(10, 3)]u8 :: [0, 0, 0, 0]
OPEN :: 5
open_ceil i32 :: divceil!(OPEN, 3)

check_i32 func(a, b, qt, qf, qc, r, m i32) bool {
	return divtrunc!(a, b) == qt and divfloor!(a, b) == qf and
	       divceil!(a, b) == qc and rem!(a, b) == r and mod!(a, b) == m
}

check_f32 func(a, b, qt, qf, qc, r, m f32) bool {
	return divtrunc!(a, b) == qt and divfloor!(a, b) == qf and
	       divceil!(a, b) == qc and rem!(a, b) == r and mod!(a, b) == m
}

check_f64 func(a, b, qt, qf, qc, r, m f64) bool {
	return divtrunc!(a, b) == qt and divfloor!(a, b) == qf and
	       divceil!(a, b) == qc and rem!(a, b) == r and mod!(a, b) == m
}

edge_rem func(a, b i32) i32 { return rem!(a, b) }
edge_mod func(a, b i32) i32 { return mod!(a, b) }

main func() i32 {
	if COUNT != 4 or items.len != 4 or open_ceil != 2 { return 1 }
	if !check_i32(5, 3, 1, 1, 2, 2, 2) { return 2 }
	if !check_i32(5, -3, -1, -2, -1, 2, -1) { return 3 }
	if !check_i32(-5, 3, -1, -2, -1, -2, 1) { return 4 }
	if !check_i32(-5, -3, 1, 1, 2, -2, -2) { return 5 }
	if divtrunc!(u32(5), u32(3)) != 1 or divfloor!(u32(5), u32(3)) != 1 or
	   divceil!(u32(5), u32(3)) != 2 or rem!(u32(5), u32(3)) != 2 or mod!(u32(5), u32(3)) != 2 { return 6 }
	if divexact!(i32(6), i32(3)) != 2 or divexact!(u32(6), u32(3)) != 2 { return 7 }
	if !check_f32(f32(5.0), f32(3.0), f32(1.0), f32(1.0), f32(2.0), f32(2.0), f32(2.0)) or
	   !check_f32(f32(5.0), f32(-3.0), f32(-1.0), f32(-2.0), f32(-1.0), f32(2.0), f32(-1.0)) or
	   !check_f32(f32(-5.0), f32(3.0), f32(-1.0), f32(-2.0), f32(-1.0), f32(-2.0), f32(1.0)) or
	   !check_f32(f32(-5.0), f32(-3.0), f32(1.0), f32(1.0), f32(2.0), f32(-2.0), f32(-2.0)) { return 8 }
	if !check_f64(5.0, 3.0, 1.0, 1.0, 2.0, 2.0, 2.0) or
	   !check_f64(5.0, -3.0, -1.0, -2.0, -1.0, 2.0, -1.0) or
	   !check_f64(-5.0, 3.0, -1.0, -2.0, -1.0, -2.0, 1.0) or
	   !check_f64(-5.0, -3.0, 1.0, 1.0, 2.0, -2.0, -2.0) { return 9 }
	if divexact!(f32(6.0), f32(3.0)) != 2.0 or divexact!(f64(6.0), f64(3.0)) != 2.0 { return 10 }
	if edge_rem(-2147483648, -1) != 0 or edge_mod(-2147483648, -1) != 0 { return 11 }
	return 0
}
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	status := compiler_core.compile_package(directory, output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
division_builtins_trap_for_runtime_zero_overflow_and_inexact_results :: proc(t: ^testing.T) {
	Case :: struct {
		name:      string,
		type_name: string,
		left:      string,
		right:     string,
	}
	cases := [?]Case{
		{name="divtrunc", type_name="i32", left="1", right="0"},
		{name="divfloor", type_name="f32", left="f32(1.0)", right="f32(0.0)"},
		{name="divexact", type_name="f64", left="1.0", right="0.0"},
		{name="divceil", type_name="i32", left="1", right="0"},
		{name="rem", type_name="f32", left="f32(1.0)", right="f32(0.0)"},
		{name="mod", type_name="f64", left="1.0", right="0.0"},
		{name="divexact", type_name="i32", left="5", right="3"},
		{name="divtrunc", type_name="i32", left="-2147483648", right="-1"},
		{name="divfloor", type_name="i32", left="-2147483648", right="-1"},
		{name="divexact", type_name="i32", left="-2147483648", right="-1"},
		{name="divceil", type_name="i32", left="-2147483648", right="-1"},
	}
	for test_case, index in cases {
		directory := fmt.aprintf("/tmp/brolang-test-division-trap-%d", index)
		main_path := fmt.aprintf("%s/main.bro", directory)
		output := fmt.aprintf("/tmp/brolang-test-division-trap-output-%d", index)
		text := fmt.aprintf(
			"invoke func(a, b %s) %s {{ return %s!(a, b) }}\nmain func() void {{ _ = invoke(%s, %s) }}\n",
			test_case.type_name, test_case.type_name, test_case.name, test_case.left, test_case.right,
		)
		_ = os2.remove_all(directory)
		_ = os.remove(output)
		testing.expect(t, os.make_directory(directory) == nil)
		testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
		status := compiler_core.compile_package(directory, output)
		testing.expect_value(t, status, 0)
		state := run_executable(output)
		testing.expect(t, !state.success)
		_ = os.remove(output)
		_ = os2.remove_all(directory)
		delete(text)
		delete(output)
		delete(main_path)
		delete(directory)
	}
}

@(test)
qualified_division_builtin_names_resolve_as_package_functions :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-qualified-division"
	math_directory := "/tmp/brolang-test-qualified-division/math"
	app_directory := "/tmp/brolang-test-qualified-division/app"
	math_path := "/tmp/brolang-test-qualified-division/math/math.bro"
	main_path := "/tmp/brolang-test-qualified-division/app/main.bro"
	output := "/tmp/brolang-test-qualified-division-output"
	math_text := `divfloor func(a, b i32) i32 { return a + b }
`
	main_text := `math :: import "../math"
main func() i32 { return math.divfloor(20, 22) }
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.make_directory(math_directory) == nil)
	testing.expect(t, os.make_directory(app_directory) == nil)
	testing.expect(t, os.write_entire_file(math_path, transmute([]byte)math_text))
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)main_text))
	status := compiler_core.compile_package(app_directory, output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 42)
}

@(test)
division_builtins_emit_guards_rounding_and_single_integer_divisions :: proc(t: ^testing.T) {
	text := `floor_i32 func(a, b i32) i32 { return divfloor!(a, b) }
ceil_i32 func(a, b i32) i32 { return divceil!(a, b) }
exact_i32 func(a, b i32) i32 { return divexact!(a, b) }
floor_u32 func(a, b u32) u32 { return divfloor!(a, b) }
rem_i16 func(a, b i16) i16 { return rem!(a, b) }
mod_i16 func(a, b i16) i16 { return mod!(a, b) }
floor_f32 func(a, b f32) f32 { return divfloor!(a, b) }
ceil_f64 func(a, b f64) f64 { return divceil!(a, b) }
exact_f32 func(a, b f32) f32 { return divexact!(a, b) }
rem_f64 func(a, b f64) f64 { return rem!(a, b) }
mod_f32 func(a, b f32) f32 { return mod!(a, b) }
main func() void {
	_ = floor_i32(5, 3)
	_ = ceil_i32(5, 3)
	_ = exact_i32(6, 3)
	_ = floor_u32(5, 3)
	_ = rem_i16(5, 3)
	_ = mod_i16(5, 3)
	_ = floor_f32(f32(5.0), f32(3.0))
	_ = ceil_f64(5.0, 3.0)
	_ = exact_f32(f32(6.0), f32(3.0))
	_ = rem_f64(5.0, 3.0)
	_ = mod_f32(f32(5.0), f32(3.0))
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, strings.count(llvm_text, "sdiv i32"), 3)
	testing.expect(t, !strings.contains(llvm_text, "srem i32"))
	testing.expect(t, strings.contains(llvm_text, "udiv i32"))
	testing.expect(t, strings.contains(llvm_text, "srem i16"))
	testing.expect(t, strings.contains(llvm_text, "remspecial"))
	testing.expect(t, strings.contains(llvm_text, "divzero_trap"))
	testing.expect(t, strings.contains(llvm_text, "divovf_trap"))
	testing.expect(t, strings.contains(llvm_text, "call float @llvm.floor.f32"))
	testing.expect(t, strings.contains(llvm_text, "call double @llvm.ceil.f64"))
	testing.expect(t, strings.contains(llvm_text, "call float @llvm.trunc.f32"))
	testing.expect(t, strings.contains(llvm_text, "frem double"))
}

@(test)
distinct_types_preserve_nominal_identity_and_backing_representation :: proc(t: ^testing.T) {
	text := `Point :: struct {
	x i32
	y i32
}
UserID :: distinct u32
OtherID :: distinct u32
PointID :: distinct Point
Bytes :: distinct [2]u8
WrappedID :: distinct UserID
static_id UserID :: UserID(42)
take func(value UserID) UserID {
	return value
}
main func() i32 {
	id UserID :: UserID(7)
	copy UserID = take(id)
	maybe ?UserID = copy
	pointer @UserID = &copy
	point PointID :: PointID(Point { x = 1, y = 2 })
	bytes Bytes :: Bytes([3, 4])
	wrapped WrappedID :: WrappedID(id)
	_ = maybe
	_ = pointer
	_ = point
	_ = bytes
	_ = wrapped
	return 0
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	user_id := types.find_named(&ast_module.type_store, 0, u32(symbol.intern(&symbols, "UserID")))
	other_id := types.find_named(&ast_module.type_store, 0, u32(symbol.intern(&symbols, "OtherID")))
	point_id := types.find_named(&ast_module.type_store, 0, u32(symbol.intern(&symbols, "PointID")))
	point := types.find_named(&ast_module.type_store, 0, u32(symbol.intern(&symbols, "Point")))
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, user_id != other_id)
	testing.expect(t, user_id != types.U32)
	testing.expect(t, types.is_distinct(user_id, &ast_module.type_store))
	testing.expect_value(t, types.runtime_representation(user_id, &ast_module.type_store), types.U32)
	testing.expect_value(t, types.runtime_representation(point_id, &ast_module.type_store), point)
	testing.expect_value(t, types.size(user_id, &ast_module.type_store), types.size(types.U32, &ast_module.type_store))
	testing.expect(t, hir_module.globals[0].is_static)
	testing.expect_value(t, hir_module.globals[0].static_value, i64(42))
	testing.expect(t, strings.contains(llvm_text, "@bro.g.0 = internal constant i32 42"))
	testing.expect(t, strings.contains(llvm_text, "select i1 true, i32"))

	retype_count := 0
	for function in ir_module.functions {
		for instruction in function.instructions {
			retype_count += 1 if instruction.op == .Retype else 0
		}
	}
	testing.expect_value(t, retype_count, 4)
}

@(test)
distinct_types_reject_implicit_conversions_operators_and_invalid_backings :: proc(t: ^testing.T) {
	text := `Opaque :: opaque
UserID :: distinct u32
OtherID :: distinct u32
BadInt :: distinct int
BadVoid :: distinct void
BadFunction :: distinct c_func() void
BadOpaque :: distinct Opaque
foreign c_func(value UserID) void
foreign_pointer c_func(value @UserID) void
main func() void {
	raw u32 = 1
	id UserID = raw
	backing u32 = UserID(2)
	other OtherID = UserID(3)
	narrow u8 = 4
	_ = UserID(narrow)
	_ = UserID()
	_ = UserID(1, 2)
	left UserID :: UserID(5)
	right UserID :: UserID(6)
	_ = left + right
	_ = left == right
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	invalid_backing_count := 0
	implicit_conversion_count := 0
	found_exact := false
	found_arity := false
	found_arithmetic := false
	found_comparison := false
	foreign_signature_count := 0
	for diagnostic in diagnostics.items {
		invalid_backing_count += 1 if strings.contains(diagnostic.message, "requires a concrete runtime backing type") else 0
		implicit_conversion_count += 1 if strings.contains(diagnostic.message, "cannot implicitly convert") else 0
		found_exact = found_exact || strings.contains(diagnostic.message, "requires an exact u32 value, got u8")
		found_arity = found_arity || strings.contains(diagnostic.message, "expects 1 argument")
		found_arithmetic = found_arithmetic || strings.contains(diagnostic.message, "arithmetic requires compatible numeric operands")
		found_comparison = found_comparison || strings.contains(diagnostic.message, "comparison requires compatible numeric operands")
		foreign_signature_count += 1 if strings.contains(diagnostic.message, "requires concrete parameter types") else 0
	}
	testing.expect_value(t, invalid_backing_count, 4)
	testing.expect(t, implicit_conversion_count >= 3)
	testing.expect(t, found_exact)
	testing.expect(t, found_arity)
	testing.expect(t, found_arithmetic)
	testing.expect(t, found_comparison)
	testing.expect_value(t, foreign_signature_count, 2)
}

@(test)
type_and_function_names_cannot_shadow :: proc(t: ^testing.T) {
	text := `Value :: distinct u32
Value func(value i32) i32 {
	return value
}
main func() i32 {
	return Value(42)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "function 'Value' shadows visible type")
	}
	testing.expect(t, found)
}

@(test)
distinct_types_compile_and_run_across_packages :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-distinct-types"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/distinct_types", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
native_enums_preserve_identity_members_and_integer_representation :: proc(t: ^testing.T) {
	text := `Animal :: enum {
	dog
	cat
	bird
}
Nat :: enum(u16) {
	one = 1
	two
	five = 5
}
global Animal :: Animal.dog
take func(value Animal) Animal {
	return value
}
identity c_func(value Nat) Nat {
	return value
}
variadic c_func(marker c_int, ...) c_int
main func() i32 {
	value Animal = .cat
	values [2]Animal :: [.dog, Animal.bird]
	number Nat = identity(.two)
	ordinal c_int :: c_int(number)
	_ = variadic(0, number)
	if take(value) == Animal.cat and values[0] != values[1] and number == Nat.two and ordinal == 2 {
		return 0
	}
	return 1
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	animal := types.find_named(&ast_module.type_store, 0, u32(symbol.intern(&symbols, "Animal")))
	nat := types.find_named(&ast_module.type_store, 0, u32(symbol.intern(&symbols, "Nat")))
	animal_node, animal_ok := types.node(&ast_module.type_store, animal)
	nat_node, nat_ok := types.node(&ast_module.type_store, nat)
	animal_members := types.enum_members_for(&ast_module.type_store, animal)
	nat_members := types.enum_members_for(&ast_module.type_store, nat)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, animal_ok && nat_ok)
	testing.expect(t, types.is_enum(animal, &ast_module.type_store))
	testing.expect_value(t, animal_node.child, types.U16)
	testing.expect(t, !animal_node.explicit_backing)
	testing.expect_value(t, nat_node.child, types.U16)
	testing.expect(t, nat_node.explicit_backing)
	testing.expect_value(t, len(animal_members), 3)
	testing.expect_value(t, animal_members[0].value, i128(1))
	testing.expect_value(t, animal_members[2].value, i128(3))
	testing.expect_value(t, nat_members[0].value, i128(1))
	testing.expect_value(t, nat_members[1].value, i128(2))
	testing.expect_value(t, nat_members[2].value, i128(5))
	testing.expect(t, strings.contains(llvm_text, "zext i16"))
	testing.expect_value(t, types.runtime_representation(animal, &ast_module.type_store), types.U16)
	testing.expect_value(t, types.size(animal, &ast_module.type_store), u64(2))
	testing.expect(t, hir_module.globals[0].is_static)
	testing.expect_value(t, hir_module.globals[0].static_value, i64(1))
	testing.expect(t, strings.contains(llvm_text, "@bro.g.0 = internal constant i16 1"))
	found_promotion := false
	for function in ir_module.functions {
		for instruction in function.instructions {
			found_promotion = found_promotion || instruction.op == .C_Vararg_Promote
		}
	}
	testing.expect(t, found_promotion)
}

@(test)
keywords_are_valid_enum_members_and_tagged_union_variants :: proc(t: ^testing.T) {
	testing.expect(t, token.is_keyword(.Keyword_Func))
	testing.expect(t, token.is_keyword(.Keyword_Hide))
	testing.expect(t, token.is_keyword(.Keyword_C_Longdouble))
	testing.expect(t, !token.is_keyword(.Identifier))
	testing.expect(t, !token.is_keyword(.Underscore))

	text := `TokenKind :: enum {
	if
	else
	return
}
Token :: union(TokenKind) {
	if i32
	else void
	return i32
}
kind func(value bool) TokenKind {
	if value {
		return .if
	}
	return TokenKind.else
}
main func() i32 {
	first TokenKind = kind(true)
	second TokenKind = .return
	a Token = Token{ if = 1 }
	b Token = Token{ else }
	c Token = .return{2}
	total i32 = a.if + c.return
	match first {
		.if: total = total + 1
		.else: total = total + 2
		.return: total = total + 3
	}
	match b {
		.if |value|: total = total + value
		.else: total = total + 4
		.return |value|: total = total + value
	}
	_ = second
	return total
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)
	ir_module := lower.lower(&hir_module)
	defer ir.destroy_module(&ir_module)
	llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)
	defer delete(llvm_text)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, len(llvm_text) > 0)
}

@(test)
keyword_names_remain_invalid_for_struct_fields :: proc(t: ^testing.T) {
	text := `Bad :: struct {
	if i32
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "expected a struct field name")
	}
	testing.expect(t, found)
}

@(test)
unbacked_enum_uses_global_u16_backing :: proc(t: ^testing.T) {
	builder := strings.builder_make()
	defer strings.builder_destroy(&builder)
	strings.write_string(&builder, "Large :: enum {\n")
	for index in 0..<257 {
		fmt.sbprintf(&builder, "value_%d\n", index)
	}
	strings.write_string(&builder, "}\nmain func() void {}\n")
	source_file := source.Source{path="test.bro", text=strings.to_string(builder)}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	large := types.find_named(&module.type_store, 0, u32(symbol.intern(&symbols, "Large")))
	item, ok := types.node(&module.type_store, large)
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, ok)
	testing.expect_value(t, item.child, types.U16)
	testing.expect_value(t, len(types.enum_members_for(&module.type_store, large)), 257)
}

@(test)
native_enum_invalid_declarations_and_operations_are_diagnosed :: proc(t: ^testing.T) {
	text := `Empty :: enum {}
Dense :: enum {
	zero = 0
	one
}
BadBacking :: enum(f32) {
	value
}
Duplicate :: enum(u8) {
	value
	value
}
Jumbled :: enum(i8) {
	second = 2
	first = 1
}
Overflow :: enum(u8) {
	value = 256
}
Other :: enum {
	value
}
foreign c_func(value Dense) void
allowed c_func(value Overflow) Overflow
main func() void {
	dense Dense = Other.value
	_ = Dense.zero + Dense.one
	_ = Dense.zero < Dense.one
	_ = Dense.missing
	_ = .zero
	_ = dense
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found_empty := false
	found_unbacked_value := false
	found_backing := false
	found_duplicate := false
	found_order := false
	found_overflow := false
	found_foreign := false
	found_conversion := false
	found_arithmetic := false
	found_comparison := false
	found_member := false
	found_context := false
	for diagnostic in diagnostics.items {
		found_empty = found_empty || strings.contains(diagnostic.message, "require at least one member")
		found_unbacked_value = found_unbacked_value || strings.contains(diagnostic.message, "explicit enum values require a backing type")
		found_backing = found_backing || strings.contains(diagnostic.message, "requires a concrete integer backing type")
		found_duplicate = found_duplicate || strings.contains(diagnostic.message, "duplicate enum member")
		found_order = found_order || strings.contains(diagnostic.message, "strictly increasing")
		found_overflow = found_overflow || strings.contains(diagnostic.message, "does not fit in u8")
		found_foreign = found_foreign || strings.contains(diagnostic.message, "requires concrete parameter types")
		found_conversion = found_conversion || strings.contains(diagnostic.message, "cannot implicitly convert")
		found_arithmetic = found_arithmetic || strings.contains(diagnostic.message, "arithmetic requires compatible numeric operands")
		found_comparison = found_comparison || strings.contains(diagnostic.message, "enum values only support")
		found_member = found_member || strings.contains(diagnostic.message, "unknown enum member")
		found_context = found_context || strings.contains(diagnostic.message, "requires an enum context")
	}
	testing.expect(t, found_empty)
	testing.expect(t, found_unbacked_value)
	testing.expect(t, found_backing)
	testing.expect(t, found_duplicate)
	testing.expect(t, found_order)
	testing.expect(t, found_overflow)
	testing.expect(t, found_foreign)
	testing.expect(t, found_conversion)
	testing.expect(t, found_arithmetic)
	testing.expect(t, found_comparison)
	testing.expect(t, found_member)
	testing.expect(t, found_context)
}

@(test)
native_enums_compile_and_run_across_packages :: proc(t: ^testing.T) {
	output := "/tmp/brolang-test-enums"
	defer _ = os.remove(output)
	status := compiler_core.compile_package("examples/programs/enums", output)
	testing.expect_value(t, status, 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
translate_c_emits_native_bindings_and_round_trips :: proc(t: ^testing.T) {
	result := cimport.init_result(context.allocator)

	// type table: [0]=c_int, [1]=c_ulong, [2]=Record(Pair),
	// [3]=Function(c_int)->c_int, [4]=Pointer->Function (callback),
	// [5]=void, [6]=Pointer->void
	append(&result.types, cimport.Type{kind = .C_Int, child = cimport.INVALID_TYPE})
	append(&result.types, cimport.Type{kind = .C_Ulong, child = cimport.INVALID_TYPE})
	append(&result.types, cimport.Type{kind = .Record, record = 0, child = cimport.INVALID_TYPE})
	func_params := []cimport.Type_Id{cimport.Type_Id(0)}
	append(&result.types, cimport.Type{kind = .Function, params = func_params, child = cimport.Type_Id(0)})
	append(&result.types, cimport.Type{kind = .Pointer, child = cimport.Type_Id(3)})
	append(&result.types, cimport.Type{kind = .Void, child = cimport.INVALID_TYPE})
	append(&result.types, cimport.Type{kind = .Pointer, child = cimport.Type_Id(5), mutable = true})

	// record 0: Pair { left c_int; right c_int }
	pair_fields: [dynamic]cimport.Field
	append(&pair_fields, cimport.Field{name = "left", type = cimport.Type_Id(0)})
	append(&pair_fields, cimport.Field{name = "right", type = cimport.Type_Id(0)})
	append(&result.records, cimport.Record{name = "Pair", fields = pair_fields, kind = .Struct, complete = true})

	// record 1: union Choice -> commented (no native spelling)
	choice_fields: [dynamic]cimport.Field
	append(&choice_fields, cimport.Field{name = "tag", type = cimport.Type_Id(0)})
	append(&result.records, cimport.Record{name = "Choice", fields = choice_fields, kind = .Union, complete = true})

	// record 2: incomplete struct -> opaque
	append(&result.records, cimport.Record{name = "Handle", kind = .Struct, complete = false})

	// typedef aliases: a scalar, a callback function pointer, and a C void pointer
	append(&result.aliases, cimport.Alias{name = "Size", type = cimport.Type_Id(1)})
	append(&result.aliases, cimport.Alias{name = "Mapper", type = cimport.Type_Id(4)})
	append(&result.aliases, cimport.Alias{name = "RawPtr", type = cimport.Type_Id(6)})

	add_params := []cimport.Type_Id{cimport.Type_Id(0), cimport.Type_Id(0)}
	add_param_names := []string{"a", "b"}
	append(&result.functions, cimport.Function{name = "imported_add", params = add_params, param_names = add_param_names, result = cimport.Type_Id(0)})
	raw_params := []cimport.Type_Id{cimport.Type_Id(6)}
	raw_param_names := []string{"ptr"}
	append(&result.functions, cimport.Function{name = "consume_raw", params = raw_params, param_names = raw_param_names, result = cimport.Type_Id(5)})

	append(&result.macros, cimport.Macro_Constant{
		name = "MAX_LEN",
		type = cimport.Type_Id(0),
		value = {kind = .Integer, type = cimport.Type_Id(0), integer = 256},
	})

	// external variable -> commented (no native spelling)
	append(&result.variables, cimport.Variable{name = "some_global", type = cimport.Type_Id(0), mutable = true})

	result.available = true

	output := translatec.emit(&result, "test.h")
	defer delete(output)
	defer {
		delete(result.types)
		delete(result.records)
		delete(result.aliases)
		delete(result.functions)
		delete(result.variables)
		delete(result.macros)
		delete(pair_fields)
		delete(choice_fields)
	}

	testing.expect(t, strings.contains(output, "Pair :: c_struct {"))
	testing.expect(t, strings.contains(output, "\tleft c_int"))
	testing.expect(t, strings.contains(output, "\tright c_int"))
	testing.expect(t, strings.contains(output, "Size :: alias c_ulong"))
	// Function-pointer types carry no parameter names, so the callback renders `_`.
	testing.expect(t, strings.contains(output, "Mapper :: alias ?*c_func(_ c_int) c_int"))
	testing.expect(t, strings.contains(output, "RawPtr :: alias ?*mut anyopaque"))
	testing.expect(t, strings.contains(output, "Handle :: opaque"))
	// Real C parameter names are used when present.
	testing.expect(t, strings.contains(output, "imported_add c_func(a c_int, b c_int) c_int"))
	testing.expect(t, strings.contains(output, "consume_raw c_func(ptr ?*mut anyopaque) void"))
	testing.expect(t, strings.contains(output, "MAX_LEN c_int :: 256"))
	testing.expect(t, strings.contains(output, "# unsupported in bindings: C union 'Choice'"))
	testing.expect(t, strings.contains(output, "# unsupported in bindings: external variable 'some_global'"))

	// Round-trip: the emitted source must lex + parse with zero diagnostics.
	// This guards render_type against drift from loader.translate_c_type and
	// exercises the new `alias` declaration syntax.
	source_file := source.Source{path = "bindings.bro", text = output}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)
	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
translate_c_package_deduplicates_compatible_declarations :: proc(t: ^testing.T) {
	first := cimport.init_result(context.allocator)
	second := cimport.init_result(context.allocator)
	defer {
		delete(first.types)
		delete(first.records[0].fields)
		delete(first.records)
		delete(first.functions)
		delete(first.macros)
		delete(second.types)
		delete(second.records[0].fields)
		delete(second.records)
		delete(second.functions)
		delete(second.macros)
	}

	append(&first.types, cimport.Type{kind=.C_Int, child=cimport.INVALID_TYPE})
	append(&first.types, cimport.Type{kind=.Record, record=0, child=cimport.INVALID_TYPE})
	append(&first.types, cimport.Type{kind=.Pointer, child=1, mutable=true})
	append(&second.types, ..first.types[:])
	first_fields: [dynamic]cimport.Field
	second_fields: [dynamic]cimport.Field
	append(&first_fields, cimport.Field{name="value", type=0})
	append(&second_fields, cimport.Field{name="value", type=0})
	append(&first.records, cimport.Record{
		identity="shared-anonymous-record",
		kind=.Struct,
		complete=true,
		fields=first_fields,
	})
	append(&second.records, cimport.Record{
		identity="shared-anonymous-record",
		kind=.Struct,
		complete=true,
		fields=second_fields,
	})
	first_params := [?]cimport.Type_Id{0}
	second_params := [?]cimport.Type_Id{0}
	use_record_params := [?]cimport.Type_Id{2}
	first_names := [?]string{"left"}
	second_names := [?]string{"right"}
	append(&first.functions, cimport.Function{
		name="shared",
		params=first_params[:],
		param_names=first_names[:],
		result=0,
	})
	append(&second.functions, cimport.Function{
		name="shared",
		params=second_params[:],
		param_names=second_names[:],
		result=0,
	})
	append(&second.functions, cimport.Function{
		name="use_record",
		params=use_record_params[:],
		result=0,
	})
	append(&first.macros, cimport.Macro_Constant{
		name="SHARED_VALUE",
		type=0,
		value={kind=.Integer, type=0, integer=7},
	})
	append(&second.macros, first.macros[0])

	inputs := [?]translatec.Package_Input{
		{result=&first, header="first.h", name="first.bro"},
		{result=&second, header="second.h", name="second.bro"},
	}
	outputs, generation_error := translatec.emit_package(inputs[:])
	defer translatec.destroy_package_outputs(outputs)
	defer delete(generation_error)
	testing.expect_value(t, generation_error, "")
	testing.expect_value(t, len(outputs), 2)
	if len(outputs) == 2 {
		combined := fmt.tprintf("%s%s", outputs[0].source, outputs[1].source)
		testing.expect_value(t, count_substring_occurrences(combined, "shared c_func("), 1)
		testing.expect_value(t, count_substring_occurrences(combined, "SHARED_VALUE c_int :: 7"), 1)
		testing.expect(t, strings.contains(outputs[0].source, "__c_first_bro_record_0 :: c_struct"))
		testing.expect(t, strings.contains(outputs[1].source, "use_record c_func(_ ?*mut __c_first_bro_record_0) c_int"))
	}

	second.macros[0].value.integer = 8
	conflicting, conflict_error := translatec.emit_package(inputs[:])
	defer translatec.destroy_package_outputs(conflicting)
	defer delete(conflict_error)
	testing.expect_value(t, len(conflicting), 0)
	testing.expect(t, strings.contains(conflict_error, "conflicting generated C declaration 'SHARED_VALUE'"))
}

@(test)
translate_c_package_cli_requires_unambiguous_outputs :: proc(t: ^testing.T) {
	testing.expect_value(t, run_translate_c([]string{
		"brolang", "--translate-c", "first.h", "second.h",
	}), 2)
	testing.expect_value(t, run_translate_c([]string{
		"brolang", "--translate-c", "a/same.h", "b/same.h", "--output-dir", "/tmp/unused",
	}), 2)
}

@(test)
sink_named_parameters_are_allowed_and_not_duplicates :: proc(t: ^testing.T) {
	// Generated bindings use `_` for unnamed C params; the parser must accept it and
	// the checker must not flag repeated `_` as duplicate parameters.
	text := `foo c_func(_ c_int, _ c_int) c_int
main func() void {
	_ = foo(1, 2)
}
`
	source_file := source.Source{path = "test.bro", text = text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	for diagnostic in diagnostics.items {
		testing.expect(t, !strings.contains(diagnostic.message, "duplicate parameter"))
		testing.expect(t, !strings.contains(diagnostic.message, "expected parameter name"))
	}
	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
contextual_inference_resolves_signed_const_chain :: proc(t: ^testing.T) {
	text := `X :: 1000
Y int :: X
Z i32 :: Y
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	// The concrete i32 on Z flows backward through Y to the open constant X, so all
	// three resolve to i32 instead of X/Y staying at the literal's smallest signed type.
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, types.equal(hir_module.globals[0].type, types.I32))
	testing.expect(t, types.equal(hir_module.globals[1].type, types.I32))
	testing.expect(t, types.equal(hir_module.globals[2].type, types.I32))
}

@(test)
contextual_inference_open_constants_adopt_unsigned_demand :: proc(t: ^testing.T) {
	text := `A :: 10
B u16 :: A
P :: 10
R u32 :: P
N :: 42
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	// An open constant is sign-agnostic until used: it adopts the unsigned family a use
	// demands (the literal's signed default would block this). Unconstrained N defaults.
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, types.equal(hir_module.globals[0].type, types.U16)) // A
	testing.expect(t, types.equal(hir_module.globals[1].type, types.U16)) // B
	testing.expect(t, types.equal(hir_module.globals[2].type, types.U32)) // P
	testing.expect(t, types.equal(hir_module.globals[3].type, types.U32)) // R
	testing.expect(t, types.equal(hir_module.globals[4].type, types.I8))  // N
}

@(test)
contextual_inference_rejects_constant_that_does_not_fit_demand :: proc(t: ^testing.T) {
	text := `BIG :: 100000
C u8 :: BIG
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	// 100000 does not fit u8, so the demand is rejected, BIG defaults to i32, and the
	// genuine mismatch surfaces at the use's boundary coercion.
	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "cannot implicitly convert i32 to u8")
	}
	testing.expect(t, found)
}

@(test)
contextual_inference_does_not_cross_call_boundaries :: proc(t: ^testing.T) {
	text := `echo func(p int) int { return p }
A :: 10
R u32 :: echo(A)
main func() void {}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	// The u32 demand on R must not flow through echo into A (that is L3, deferred). A
	// stays at its default i8, so the call result fails to coerce to u32.
	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "cannot implicitly convert i8 to u32")
	}
	testing.expect(t, found)
}

@(test)
contextual_inference_resolves_locals_like_globals :: proc(t: ^testing.T) {
	text := `take_u16 func(_ u16) void {}
get func() u16 {
	c :: 10
	return c
}
main func() void {
	x :: 1000
	y int :: x
	z i32 :: y
	a :: 10
	b u16 :: a
	n :: 5
	take_u16(n)
	_ = z
	_ = b
	_ = get()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	// The same backward propagation works for locals: a constant local adopts the
	// unsigned/wider type a later use demands (declaration, call argument, or return),
	// so none of these need an explicit annotation. Without it, i8->u16/u32 would error.
	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
contextual_inference_demand_from_function_body_reaches_global :: proc(t: ^testing.T) {
	text := `take_u16 func(_ u16) void {}
G :: 10
main func() void {
	take_u16(G)
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	// A demand originating inside a function body (passing G to a u16 parameter) flows
	// back to the open-constant global G, resolving it to u16.
	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, types.equal(hir_module.globals[0].type, types.U16))
}

@(test)
contextual_inference_flows_through_compound_assignment :: proc(t: ^testing.T) {
	text := `main func() void {
	s :: 5
	v u16 = 0
	v += s
	_ = v
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	// `s` is used only as the RHS of `v += s`. The assignment target's type (u16) is
	// demanded backward onto `s`, resolving the open constant; without it the compound
	// assignment would report "arithmetic requires compatible numeric operands".
	testing.expect_value(t, len(diagnostics.items), 0)
}

@(test)
contextual_inference_resolves_open_global_arithmetic_across_uses :: proc(t: ^testing.T) {
	text := `take_ci func(_ c_int) void {}
W :: 800
Z :: 40
STEP :: 5
main func() void {
	take_ci(W)
	x int = W - Z
	take_ci(Z)
	x += STEP
	take_ci(x)
	_ = x
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	// `W - Z` mixes two open-constant globals while `Z`'s c_int use comes only after the
	// arithmetic, and `STEP` is used only in a compound assignment. With deferred defaulting
	// an undemanded open global stays typeless during the fixpoint instead of leaking a
	// provisional i16 default, so W/Z/STEP all resolve to c_int. Previously this reported
	// "arithmetic requires compatible numeric operands" / "cannot implicitly convert i16 to c_int".
	testing.expect_value(t, len(diagnostics.items), 0)
	for global in hir_module.globals {
		name := symbol.resolve(&symbols, global.name)
		if name == "W" || name == "Z" || name == "STEP" {
			testing.expect(t, types.equal(global.type, types.C_INT))
		}
	}
}

@(test)
contextual_inference_rejects_local_constant_that_does_not_fit :: proc(t: ^testing.T) {
	text := `main func() void {
	big :: 100000
	c u8 :: big
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	// 100000 does not fit u8, so big keeps its i32 default and the use errors.
	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "cannot implicitly convert i32 to u8")
	}
	testing.expect(t, found)
}

@(test)
contextual_inference_flows_through_numeric_arithmetic :: proc(t: ^testing.T) {
	text := `take_u16 func(_ u16) void {}
take_f32 func(_ f32) void {}
G :: 10
H u16 :: G + 2
GF :: 1.5
HF f32 :: GF + 2.5
CG :: 5
CFG :: 1.0
get func() f32 {
	seed f32 :: 2.0
	c :: seed + 3.0
	d :: 4.0 + seed
	return c + d
}
main func() void {
	a :: 10
	b u16 :: a + 2
	x :: 1.5
	y f32 :: x + 2.5
	z f32 :: 2.5 + x
	call_i :: 7
	call_f :: 1.25
	take_u16(call_i + 3)
	take_f32(call_f + 3.0)
	take_u16(CG + 1)
	take_f32(CFG + 1.0)
	_ = b
	_ = y
	_ = z
	_ = H
	_ = HF
	_ = get()
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect_value(t, len(diagnostics.items), 0)

	global_ok := 0
	for global in hir_module.globals {
		name := symbol.resolve(&symbols, global.name)
		switch name {
		case "G", "H", "CG":
			global_ok += 1 if types.equal(global.type, types.U16) else 0
		case "GF", "HF", "CFG":
			global_ok += 1 if types.equal(global.type, types.F32) else 0
		}
	}
	testing.expect_value(t, global_ok, 6)

	main_ok := 0
	get_ok := false
	for function in hir_module.functions {
		name := symbol.resolve(&symbols, function.name)
		if name == "get" {
			get_ok = types.equal(function.result, types.F32)
			for local in function.locals {
				local_name := symbol.resolve(&symbols, local.name)
				if local_name == "c" || local_name == "d" {
					main_ok += 1 if types.equal(local.type, types.F32) else 0
				}
			}
		} else if name == "main" {
			for local in function.locals {
				local_name := symbol.resolve(&symbols, local.name)
				switch local_name {
				case "a", "call_i":
					main_ok += 1 if types.equal(local.type, types.U16) else 0
				case "x", "call_f":
					main_ok += 1 if types.equal(local.type, types.F32) else 0
				}
			}
		}
	}
	testing.expect(t, get_ok)
	testing.expect_value(t, main_ok, 6)
}

@(test)
contextual_inference_rejects_non_fitting_arithmetic_demand :: proc(t: ^testing.T) {
	text := `BIG :: 100000
C u8 :: BIG + 1
main func() void {
	_ = C
}
`
	source_file := source.Source{path="test.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	found := false
	for diagnostic in diagnostics.items {
		found = found || strings.contains(diagnostic.message, "cannot implicitly convert i32 to u8")
	}
	testing.expect(t, found)
}

@(test)
missing_qualified_signature_symbol_reports_one_root_error :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-root-diagnostic"
	defer _ = os2.remove_all(directory)
	_ = os2.remove_all(directory)
	testing.expect(t, os.make_directory(directory) == nil)
	token_text := `Token :: struct { start int }
`
	lexer_text := `scan func(cursor usize) void ! missing.Error {
	token Token = Token{start = cursor}
	_ = token
}
`
	main_text := `main func() void {
	scan(1) catch |_| { return }
}
`
	testing.expect(t, os.write_entire_file(
		"/tmp/brolang-test-root-diagnostic/token.bro",
		transmute([]byte)token_text,
	))
	testing.expect(t, os.write_entire_file(
		"/tmp/brolang-test-root-diagnostic/lexer.bro",
		transmute([]byte)lexer_text,
	))
	testing.expect(t, os.write_entire_file(
		"/tmp/brolang-test-root-diagnostic/main.bro",
		transmute([]byte)main_text,
	))

	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	module, loaded := loader.load(directory, &sources, &diagnostics, &symbols)
	defer ast.destroy_module(&module)
	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect(t, loaded)
	testing.expect_value(t, len(diagnostics.items), 1)
	testing.expect_value(t, diagnostics.items[0].message, "unknown symbol 'missing'")
	formatted := source.format(&diagnostics, source.Diagnostic_Id(0))
	defer delete(formatted)
	testing.expect(t, strings.contains(formatted, "/lexer.bro:1:32"))
	testing.expect(t, strings.contains(formatted, "^^^^^^^ unknown symbol"))
	testing.expect(t, !strings.contains(formatted, "fallible expression"))
	testing.expect(t, !strings.contains(formatted, "must be consumed"))
	testing.expect(t, !strings.contains(formatted, "could not resolve the 'int' constraint"))
}

@(test)
poisoned_global_and_local_types_do_not_create_inference_fallbacks :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-poisoned-declarations"
	defer _ = os2.remove_all(directory)
	_ = os2.remove_all(directory)
	testing.expect(t, os.make_directory(directory) == nil)
	text := `bad missing.Global :: 1
main func() void {
	value absent.Local = 1
	_ = value
}
`
	testing.expect(t, os.write_entire_file(
		"/tmp/brolang-test-poisoned-declarations/main.bro",
		transmute([]byte)text,
	))

	sources := source.init_store()
	defer source.destroy_store(&sources)
	diagnostics := source.init_store_diagnostics(&sources)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	module, loaded := loader.load(directory, &sources, &diagnostics, &symbols)
	defer ast.destroy_module(&module)
	hir_module := checker.check(&module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	testing.expect(t, loaded)
	testing.expect_value(t, len(diagnostics.items), 2)
	unknown_missing := false
	unknown_absent := false
	for diagnostic in diagnostics.items {
		unknown_missing = unknown_missing || diagnostic.message == "unknown symbol 'missing'"
		unknown_absent = unknown_absent || diagnostic.message == "unknown symbol 'absent'"
		testing.expect(t, !strings.contains(diagnostic.message, "could not resolve"))
		testing.expect(t, !strings.contains(diagnostic.message, "could not infer"))
	}
	testing.expect(t, unknown_missing)
	testing.expect(t, unknown_absent)
}

named_record_field_type :: proc(
	module: ^hir.Module,
	symbols: ^symbol.Table,
	record_name, field_name: string,
) -> (types.Type, bool) {
	record := types.find_named(&module.types, 0, u32(symbol.intern(symbols, record_name)))
	if !types.is_record(record, &module.types) {
		return types.INVALID, false
	}
	field_symbol := symbol.intern(symbols, field_name)
	for field in types.fields_for(&module.types, record) {
		if field.name == u32(field_symbol) {
			return field.type, true
		}
	}
	return types.INVALID, false
}

@(test)
native_record_constraint_fields_resolve_program_wide :: proc(t: ^testing.T) {
	text := `Token :: struct { start int }
Backward :: struct { start int }
Wide :: struct { value int }
Literal :: struct { value int }
Measurement :: struct {
	ratio float
	span range
}
Payload :: union { count int }

take_usize func(value usize) usize { return value }

exercise func(cursor usize, narrow i8, wider i16, count i32) i32 {
	token Token = Token{start = cursor}
	wide Wide = Wide{value = narrow}
	wide.value = wider
	small Literal = Literal{value = 1}
	large Literal = Literal{value = 1000}
	backward Backward = Backward{start = 1}
	measurement Measurement = Measurement{ratio = 1.5, span = 0..3}
	payload Payload = Payload{count = count}
	_ = token.start
	_ = wide.value
	_ = small.value
	_ = large.value
	_ = take_usize(backward.start)
	_ = measurement.ratio
	_ = measurement.span
	_ = payload.count
	return 0
}

main func() i32 { return exercise(7, 1, 1000, 3) }
`
	source_file := source.Source{path="record_constraints.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	token_start, token_ok := named_record_field_type(&hir_module, &symbols, "Token", "start")
	backward_start, backward_ok := named_record_field_type(&hir_module, &symbols, "Backward", "start")
	wide_value, wide_ok := named_record_field_type(&hir_module, &symbols, "Wide", "value")
	literal_value, literal_ok := named_record_field_type(&hir_module, &symbols, "Literal", "value")
	ratio, ratio_ok := named_record_field_type(&hir_module, &symbols, "Measurement", "ratio")
	span, span_ok := named_record_field_type(&hir_module, &symbols, "Measurement", "span")
	count, count_ok := named_record_field_type(&hir_module, &symbols, "Payload", "count")

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect(t, token_ok && backward_ok && wide_ok && literal_ok && ratio_ok && span_ok && count_ok)
	testing.expect_value(t, token_start, types.USIZE)
	testing.expect_value(t, backward_start, types.USIZE)
	testing.expect_value(t, wide_value, types.I16)
	testing.expect_value(t, literal_value, types.I16)
	testing.expect_value(t, ratio, types.F64)
	testing.expect(t, types.is_range(span, &hir_module.types))
	testing.expect_value(t, types.child_type(span, &hir_module.types), types.I8)
	testing.expect_value(t, count, types.I32)
}

@(test)
native_record_int_field_compiles_and_runs_as_usize :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-record-field-usize"
	main_path := "/tmp/brolang-test-record-field-usize/main.bro"
	output := "/tmp/brolang-test-record-field-usize-output"
	text := `Token :: struct { start int }
main func() i32 {
	cursor usize = 7
	token Token = Token{start = cursor}
	if (token.start != cursor) return 1
	return 0
}
`
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)text))
	testing.expect_value(t, compiler_core.compile_package(directory, output), 0)
	state := run_executable(output)
	testing.expect_value(t, state.exit_code, 0)
}

@(test)
native_record_constraint_fields_report_unresolved_and_conflicting_demands :: proc(t: ^testing.T) {
	cases := [2]struct {
		text: string,
		needle: string,
	}{
		{
			text = `Token :: struct { start int }
main func() void {}
`,
			needle = "could not resolve the 'int' constraint for field 'Token.start'",
		},
		{
			text = `Token :: struct { start int }
use func(signed i32, unsigned usize) void {
	a Token = Token{start = signed}
	b Token = Token{start = unsigned}
	_ = a
	_ = b
}
main func() void { use(1, 2) }
`,
			needle = "conflicting types i32 and usize for field 'Token.start' declared as 'int'",
		},
	}
	for test_case in cases {
		source_file := source.Source{path="bad_record_constraint.bro", text=test_case.text}
		diagnostics := source.init_diagnostics(&source_file)
		symbols := symbol.init_table()
		stream := lexer.lex(&source_file, &diagnostics, &symbols)
		ast_module := parser.parse(&stream, &source_file, &diagnostics)
		hir_module := checker.check(&ast_module, &diagnostics, &symbols)
		ir_module := lower.lower(&hir_module)
		llvm_text := llvm.emit(&ir_module, &diagnostics, &symbols)

		matching := 0
		for diagnostic in diagnostics.items {
			matching += 1 if strings.contains(diagnostic.message, test_case.needle) else 0
		}
		testing.expect_value(t, matching, 1)
		testing.expect(t, len(llvm_text) > 0)

		delete(llvm_text)
		ir.destroy_module(&ir_module)
		hir.destroy_module(&hir_module)
		ast.destroy_module(&ast_module)
		delete(stream.items)
		symbol.destroy_table(&symbols)
		source.destroy_diagnostics(&diagnostics)
	}

	directory := "/tmp/brolang-test-record-field-conflict"
	main_path := "/tmp/brolang-test-record-field-conflict/main.bro"
	output := "/tmp/brolang-test-record-field-conflict-output"
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(output)
	testing.expect(t, os.make_directory(directory) == nil)
	testing.expect(t, os.write_entire_file(main_path, transmute([]byte)cases[1].text))
	testing.expect_value(t, compiler_core.compile_package(directory, output), 1)
	state := run_executable(output)
	testing.expect(t, !state.success)
}

@(test)
constraint_fields_remain_rejected_outside_named_native_records :: proc(t: ^testing.T) {
	text := `BadC :: c_struct { value int }
BadNested :: struct { values []int }

make_type func() type {
	return struct { value int }
}

main func() void {
	Generated :: @make_type()
	_ = Generated
}
`
	source_file := source.Source{path="excluded_record_constraints.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	ast_module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&ast_module)
	hir_module := checker.check(&ast_module, &diagnostics, &symbols)
	defer hir.destroy_module(&hir_module)

	record_errors := 0
	anonymous_error := false
	for diagnostic in diagnostics.items {
		record_errors += 1 if strings.contains(diagnostic.message, "record fields must have runtime value types") else 0
		anonymous_error = anonymous_error || strings.contains(diagnostic.message, "anonymous struct field 'value' requires a concrete runtime type")
	}
	c_field, c_ok := named_record_field_type(&hir_module, &symbols, "BadC", "value")
	nested_field, nested_ok := named_record_field_type(&hir_module, &symbols, "BadNested", "values")
	testing.expect_value(t, record_errors, 1)
	testing.expect(t, anonymous_error)
	testing.expect(t, c_ok && nested_ok)
	testing.expect_value(t, c_field, types.INT)
	testing.expect(t, types.is_slice(nested_field, &hir_module.types))
	testing.expect_value(t, types.child_type(nested_field, &hir_module.types), types.INT)
}

@(test)
parser_records_native_tests_and_test_imports :: proc(t: ^testing.T) {
	text := `test import "../math"

addition test {
	return
}
`
	source_file := source.Source{path="tests.bro", text=text}
	diagnostics := source.init_diagnostics(&source_file)
	defer source.destroy_diagnostics(&diagnostics)
	symbols := symbol.init_table()
	defer symbol.destroy_table(&symbols)
	stream := lexer.lex(&source_file, &diagnostics, &symbols)
	defer delete(stream.items)
	module := parser.parse(&stream, &source_file, &diagnostics)
	defer ast.destroy_module(&module)

	testing.expect_value(t, len(diagnostics.items), 0)
	testing.expect_value(t, len(module.imports), 1)
	testing.expect(t, module.imports[0].test_only)
	testing.expect_value(t, module.imports[0].alias, symbol.INVALID)
	testing.expect_value(t, len(module.functions), 1)
	testing.expect(t, module.functions[0].test)
	testing.expect_value(t, symbol.resolve(&symbols, module.functions[0].name), "addition")
}

@(test)
native_test_framework_discovers_reports_and_preserves_main :: proc(t: ^testing.T) {
	directory := "/tmp/brolang-test-native-framework"
	root := "/tmp/brolang-test-native-framework/root"
	dependency := "/tmp/brolang-test-native-framework/dependency"
	root_path := "/tmp/brolang-test-native-framework/root/main.bro"
	dependency_path := "/tmp/brolang-test-native-framework/dependency/math.bro"
	test_output := "/tmp/brolang-test-native-framework-tests"
	app_output := "/tmp/brolang-test-native-framework-app"
	_ = os2.remove_all(directory)
	defer _ = os2.remove_all(directory)
	defer _ = os.remove(test_output)
	defer _ = os.remove(app_output)
	testing.expect(t, os2.make_directory_all(root) == nil)
	testing.expect(t, os2.make_directory_all(dependency) == nil)

	root_text := `testing :: import "@std/testing"

test import "../dependency"

main func() i32 { return 77 }

root_passes test {
	try testing.expect(true)
}

root_fails test {
	try testing.expect_equal(42, 41)
}

root_continues test {
	try testing.expect(true)
}
`
	dependency_text := `testing :: import "@std/testing"

dependency_passes test {
	try testing.expect(true)
}
`
	testing.expect(t, os.write_entire_file(root_path, transmute([]byte)root_text))
	testing.expect(t, os.write_entire_file(dependency_path, transmute([]byte)dependency_text))

	app_status := compiler_core.compile_package(
		root, app_output, nil, target.DEFAULT, cimport.Options{}, ".",
	)
	testing.expect_value(t, app_status, 0)
	app_state := run_executable(app_output)
	testing.expect_value(t, app_state.exit_code, 77)

	test_status := compiler_core.compile_package(
		root, test_output, nil, target.DEFAULT, cimport.Options{}, ".", .Test,
	)
	testing.expect_value(t, test_status, 0)
	state, stdout, stderr, _ := os2.process_exec(
		os2.Process_Desc{command=[]string{test_output}},
		context.allocator,
	)
	defer delete(stdout)
	defer delete(stderr)
	output := string(stderr)
	testing.expect_value(t, state.exit_code, 1)
	testing.expect(t, strings.contains(output, "PASS root.root_passes"))
	testing.expect(t, strings.contains(output, "FAIL root.root_fails"))
	testing.expect(t, strings.contains(output, "expected 42, found 41"))
	testing.expect(t, strings.contains(output, "PASS root.root_continues"))
	testing.expect(t, strings.contains(output, "PASS dependency.dependency_passes"))
	testing.expect(t, strings.contains(output, root_path))
	testing.expect(t, strings.contains(output, "3 passed, 1 failed"))
}