prune dead specializations

compiler_tests.odin

@@ -869,6 +869,113 @@ main :: func() void {
 	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()