fallible ergonomics

compiler_tests.odin

@@ -2439,6 +2439,81 @@ main func() i32 {
 	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
+	}
+}
+main func() i32 {
+	_ = bad_error() catch 0
+	return bad_catch()
+}
+`
+	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
+	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'")
+	}
+	testing.expect(t, found_error)
+	testing.expect(t, found_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)
 errors_example_compiles_and_runs :: proc(t: ^testing.T) {
 	output := "/tmp/brolang-test-errors"