1 // RUN: %clang_cc1 %s -fsyntax-only -verify -std=c++20
2 
3 void foo() {
4   void fn(int i, int = ({ 1; })); // expected-error {{default argument may not use a GNU statement expression}}
5 
6   auto a = [](int = ({ 1; })) {}; // expected-error {{default argument may not use a GNU statement expression}}
7 
8   auto b = []<int = ({ 1; })>(){}; // expected-error {{default non-type template argument may not use a GNU statement expression}}
9 
10   void fn(int i, int j = ({{}, {}, {,}}), int k = ""); // expected-error {{default argument may not use a GNU statement expression}} expected-error {{cannot initialize a parameter of type 'int' with an lvalue of type 'const char[1]'}} expected-note {{passing argument to parameter 'k' here}}
11 }
12 
13 template <int foo = ({ 1; })> // expected-error {{default non-type template argument may not use a GNU statement expression}}
14 void f() {}
15 
16 template <int bar = ({ 1; })> // expected-error {{default non-type template argument may not use a GNU statement expression}}
17 class S {};
18 
19 template <typename Callable>
20 int bar(Callable &&Call) {
21   return Call();
22 }
23 
24 int baz() {
25   auto l = [](int a = ({ int x = 12; x; })) { // expected-error {{default argument may not use a GNU statement expression}}
26     return 1;
27   };
28   return bar(l);
29 }
30