preserve application and error inference in test builds

compiler/ast/ast.odin

@@ -227,6 +227,7 @@ Function :: struct {
 	c_abi:      bool,
 	imported:   bool,
 	generated:  bool,
+	analysis_root: bool,
 	test:       bool,
 	file_hidden: bool,
 	has_body:   bool,

compiler/checker/checker.odin

@@ -229,6 +229,7 @@ Checker :: struct {
 	sink_symbol:          symbol.Id,
 	type_symbol:          symbol.Id,
 	current_result:       types.Type,
+	inferred_test_error:  ^types.Type,
 	current_build_ctx:    ^Build_Ctx,
 	current_comptime_values: []Comptime_Value,
 	static_state:            Ct_State,
@@ -4129,6 +4130,17 @@ Infer_Frame :: struct {
 	template:  ast.Function_Id,
 }
 
+merge_inferred_test_error :: proc(checker: ^Checker, incoming: types.Type) {
+	current := checker.inferred_test_error
+	if current == nil || !types.is_valid(incoming) ||
+	   types.can_sum_widen(incoming, current^, &checker.module.types) {
+		return
+	}
+	if merged, err := types.compose_sum(&checker.module.types, current^, incoming); err == .None {
+		current^ = merged
+	}
+}
+
 infer_nested_expr :: proc(
 	checker: ^Checker,
 	expr_id: ast.Expr_Id,
@@ -4313,6 +4325,7 @@ infer_compound_expr :: proc(
 	case .Try:
 		left_expected := expected if checker.ast_module.exprs[expr.left].kind == .Call else types.INVALID
 		value := infer_nested_expr(checker, expr.left, locals, pkg, file, demanded, local_types, left_expected)
+		merge_inferred_test_error(checker, types.fallible_error(value, store))
 		return types.fallible_success(value, store) if types.kind(value, store) == .Fallible else types.INVALID
 	case .Catch:
 		left_expected := expected if checker.ast_module.exprs[expr.left].kind == .Call else types.INVALID
@@ -5488,7 +5501,16 @@ infer_spec_locals_and_result :: proc(
 	}
 
 	result := types.INVALID
+	test_error := function.error
+	previous_test_error := checker.inferred_test_error
+	checker.inferred_test_error = &test_error if function.test else nil
 	infer_statements(checker, function.body, &locals, local_types, function.pkg, function.file, demanded, &result, result_hint)
+	checker.inferred_test_error = previous_test_error
+	if function.test && !types.equal(function.error, test_error) {
+		checker.ast_module.functions[spec.template].error = test_error
+		success := types.fallible_success(checker.specs[id].result, &checker.module.types)
+		checker.specs[id].result = types.fallible(&checker.module.types, success, test_error)
+	}
 	if types.is_constraint(declared) {
 		// Narrow the inferred result to the constraint's family; an out-of-family
 		// result (e.g. returning a non-integer from an `int` function) yields
@@ -5948,6 +5970,11 @@ infer_all :: proc(checker: ^Checker) {
 		}
 	}
 
+	for function, index in checker.ast_module.functions {
+		if function.analysis_root {
+			ensure_spec(checker, ast.function_id(index), nil)
+		}
+	}
 	main_template := find_template(checker, checker.main_symbol, 0)
 	if main_template != ast.INVALID_FUNCTION {
 		ensure_spec(checker, main_template, nil)
@@ -6035,7 +6062,9 @@ infer_all :: proc(checker: ^Checker) {
 
 		for index := 0; index < len(checker.specs); index += 1 {
 			id := spec_id(index)
+			before := checker.specs[id].result
 			inferred := infer_spec_result(checker, id)
+			changed = !types.equal(before, checker.specs[id].result) || changed
 			changed = merge_inferred_type(&checker.module.types, &checker.specs[id].result, inferred) || changed
 		}
 		if len(checker.specs) != spec_count {

compiler/testing.odin

@@ -165,20 +165,28 @@ append_runner :: proc(
 	diagnostics: ^source.Diagnostics,
 	symbols: ^symbol.Table,
 	testing_pkg: ast.Package_Id,
+	testing_error: types.Type,
 	tests: []Test_Entry,
 ) {
 	builder := strings.builder_make(module.allocator)
 	defer strings.builder_destroy(&builder)
+	for entry, index in tests {
+		test := module.functions[entry.function]
+		alias := fmt.tprintf("__brolang_test_%d", index)
+		fmt.sbprintf(&builder, "hide __brolang_test_adapter_%d func() void ! __brolang_testing.Error ", index)
+		strings.write_string(&builder, "{\n\t")
+		fmt.sbprintf(&builder, "%s.%s() catch |_| ", alias, symbol.resolve(symbols, test.name))
+		strings.write_string(&builder, "{\n\t\treturn .expectation_failed\n\t}\n}\n\n")
+	}
 	strings.write_string(&builder, "main func() i32 {\n\tfailed i32 = 0\n")
 	for entry, index in tests {
 		test_id := entry.function
 		test := module.functions[test_id]
 		pkg := module.packages[test.pkg]
-		alias := fmt.tprintf("__brolang_test_%d", index)
 		name := fmt.tprintf("%s.%s", filepath.base(pkg.path), symbol.resolve(symbols, test.name))
 		strings.write_string(&builder, "\tif (!__brolang_testing.run(\"")
 		write_brolang_string(&builder, name)
-		fmt.sbprintf(&builder, "\", %s.%s)) ", alias, symbol.resolve(symbols, test.name))
+		fmt.sbprintf(&builder, "\", __brolang_test_adapter_%d)) ", index)
 		strings.write_string(&builder, "{\n\t\tfailed += 1\n\t}\n")
 	}
 	fmt.sbprintf(&builder, "\t__brolang_testing.summary(%d - failed, failed)\n", len(tests))
@@ -190,7 +198,11 @@ append_runner :: proc(
 	append(&module.files, ast.File{source=source_id, pkg=0})
 	stream := lexer.lex(&sources.items[source_id], diagnostics, symbols, module.allocator)
 	defer delete(stream.items)
+	function_start := len(module.functions)
 	parser.parse_into(&stream, &sources.items[source_id], diagnostics, module, 0, file_id)
+	for index in 0..<len(tests) {
+		module.functions[function_start+index].error = testing_error
+	}
 
 	append(&module.imports, ast.Import{
 		alias=symbol.intern(symbols, "__brolang_testing"),
@@ -271,11 +283,12 @@ prepare_tests :: proc(
 			}
 		} else if function.pkg == 0 && function.name == main_name {
 			function.generated = true
+			function.analysis_root = true
 		}
 	}
 
 	slice.sort_by(tests[:], test_entry_less)
 	inject_assertion_locations(module, sources, symbols, testing_pkg)
-	append_runner(module, sources, diagnostics, symbols, testing_pkg, tests[:])
+	append_runner(module, sources, diagnostics, symbols, testing_pkg, error_type, tests[:])
 	return true
 }