parser: fix for x in Iterator{} {, when there are no field initialisations (#21333)

Author: spytheman

vlib/v/parser/expr.v

@@ -53,7 +53,7 @@ fn (mut p Parser) check_expr(precedence int) !ast.Expr {
 			} else if p.tok.kind == .question && p.peek_tok.kind == .amp {
 				node = p.prefix_expr()
 			} else if p.inside_for_expr && p.tok.kind == .name && p.tok.lit[0].is_capital()
-				&& p.peek_tok.kind == .lcbr && p.peek_token(2).kind == .name {
+				&& p.peek_tok.kind == .lcbr && p.peek_token(2).kind in [.rcbr, .name] {
 				node = p.struct_init(p.mod + '.' + p.tok.lit, .normal, false)
 			} else {
 				if p.inside_comptime_if && p.is_generic_name() && p.peek_tok.kind != .dot {

vlib/v/tests/struct_init_on_for_expr_test.v

@@ -11,7 +11,7 @@ fn (mut iter Iterator) next() ?int {
 	return none
 }
 
-fn test_main() {
+fn test_iterator_with_field_init() {
 	for k, x in Iterator{
 		counter: 10
 	} {
@@ -24,3 +24,24 @@ fn test_main() {
 		}
 	}
 }
+
+//
+
+struct OddNumberIterator {
+mut:
+	current i64
+}
+
+fn (mut i OddNumberIterator) next() ?i64 {
+	i.current += 2
+	return i.current + 1
+}
+
+fn test_iterator_without_field_init() {
+	for x in OddNumberIterator{} {
+		dump(x)
+		if x > 10 {
+			break
+		}
+	}
+}