if-statement optional braces when single statement

compiler_tests.odin

@@ -4084,6 +4084,104 @@ conditional_unwrap_parser_captures_guard_and_parenthesized_chain :: proc(t: ^tes
 	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)
+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 {