Allow (Foo) { 1, 2 } syntax for compound literals.

releasenotes.md

@@ -430,6 +430,7 @@
 - Add `$member.get(value)` to replace `value.$eval($member.nameof)`
 - Improve the error message when the compilation does not produce any files #1390.
 - Add `fmod` implementation for nolibc.
+- Allow `(Foo) { 1, 2 }` syntax for compound literals.
 
 ### Fixes
 

src/compiler/parse_expr.c

@@ -7,6 +7,7 @@
 
 typedef Expr *(*ParseFn)(ParseContext *context, Expr *);
 static Expr *parse_subscript_expr(ParseContext *c, Expr *left);
+static Expr *parse_initializer_list(ParseContext *c, Expr *left);
 
 typedef struct
 {
@@ -840,11 +841,6 @@ static Expr *parse_grouping_expr(ParseContext *c, Expr *left)
 		case EXPR_TYPEINFO:
 		{
 			TypeInfo *info = expr->type_expr;
-			if (tok_is(c, TOKEN_LBRACE) && info->resolve_status != RESOLVE_DONE)
-			{
-				PRINT_ERROR_HERE("Unexpected start of a block '{' here. If you intended a compound literal, remove the () around the type.");
-				return poisoned_expr;
-			}
 			// Create a cast expr
 			if (rules[c->tok].prefix)
 			{
@@ -883,7 +879,7 @@ static Expr *parse_grouping_expr(ParseContext *c, Expr *left)
  *	;
  *
  */
-Expr *parse_initializer_list(ParseContext *c, Expr *left)
+static Expr *parse_initializer_list(ParseContext *c, Expr *left)
 {
 	ASSERT(!left && "Unexpected left hand side");
 	Expr *initializer_list = EXPR_NEW_TOKEN(EXPR_INITIALIZER_LIST);

src/compiler/sema_expr.c

@@ -5651,6 +5651,12 @@ static inline bool sema_expr_analyse_cast(SemaContext *context, Expr *expr, bool
 	if (invalid_cast_ref) *invalid_cast_ref = false;
 	Expr *inner = exprptr(expr->cast_expr.expr);
 	TypeInfo *type_info = type_infoptr(expr->cast_expr.type_info);
+	if (inner->expr_kind == EXPR_INITIALIZER_LIST)
+	{
+		expr->expr_kind = EXPR_COMPOUND_LITERAL;
+		expr->expr_compound_literal = (ExprCompoundLiteral) { .initializer = inner, .type_info = type_info };
+		return sema_expr_analyse_compound_literal(context, expr);
+	}
 	bool success = sema_resolve_type_info(context, type_info, RESOLVE_TYPE_ALLOW_INFER);
 	if (!sema_analyse_expr(context, inner) || !success) return false;
 
@@ -9027,8 +9033,7 @@ static inline bool sema_expr_analyse_generic_ident(SemaContext *context, Expr *e
 	Expr *parent = exprptr(expr->generic_ident_expr.parent);
 	if (parent->expr_kind != EXPR_UNRESOLVED_IDENTIFIER)
 	{
-		SEMA_ERROR(parent, "Expected an identifier to parameterize.");
-		return false;
+		RETURN_SEMA_ERROR(parent, "Expected an identifier to parameterize.");
 	}
 	Decl *symbol = sema_analyse_parameterized_identifier(context, parent->unresolved_ident_expr.path,
 														 parent->unresolved_ident_expr.ident, parent->span,

src/compiler/sema_initializers.c

@@ -836,8 +836,7 @@ bool sema_expr_analyse_initializer_list(SemaContext *context, Type *to, Expr *ex
 				expr_rewrite_to_const_zero(expr, to);
 				return true;
 			}
-			SEMA_ERROR(expr, "Pointers cannot be initialized using an initializer list, instead you need to take the address of an array.");
-			return false;
+			RETURN_SEMA_ERROR(expr, "Pointers cannot be initialized using an initializer list, instead you need to take the address of an array.");
 		case TYPE_VOID:
 		case TYPE_POISONED:
 		case TYPE_FUNC_RAW:
@@ -845,7 +844,7 @@ bool sema_expr_analyse_initializer_list(SemaContext *context, Type *to, Expr *ex
 		case TYPE_OPTIONAL:
 		case TYPE_TYPEINFO:
 		case TYPE_MEMBER:
-			break;
+			RETURN_SEMA_ERROR(expr, "You cannot use %s with an initializer list.", type_quoted_error_string(to));
 		default:
 			if (is_zero_init)
 			{
@@ -855,8 +854,7 @@ bool sema_expr_analyse_initializer_list(SemaContext *context, Type *to, Expr *ex
 			}
 			break;
 	}
-	SEMA_ERROR(expr, "'%s' cannot use compound literal initialization, did you intend to use a cast?", type_to_error_string(to));
-	return false;
+	RETURN_SEMA_ERROR(expr, "You cannot use %s with a non-empty initializer list.", type_quoted_error_string(to));
 }
 
 void const_init_rewrite_to_value(ConstInitializer *const_init, Expr *value)

test/test_suite/cast/cast_parse_fails.c3

@@ -2,7 +2,7 @@ struct Foo { int a; }
 
 fn void test2()
 {
-    int x = int{ 32 };    // #error: 'int' cannot use compound literal initialization, did you intend to use a cast
+    int x = int{ 32 };    // #error: 'int' with a non-empty initializer list
 }
 
 fn void test3()

test/test_suite/cast/cast_untyped_list_error.c3

@@ -2,5 +2,5 @@ module testing;
 
 fn void main()
 {
-	(void){}; // #error: You cannot cast 'untyped_list' to 'void'
+	(void){}; // #error: You cannot use 'void' with an initializer list
 }