clang/test/SemaCXX/GH95854.cpp

   1 // RUN: %clang_cc1 -std=c++23 -fsyntax-only -verify %s
   2
   3 struct A {
   4   union {
   5     int n = 0;
   6     int m;
   7   };
   8 };
   9 const A a;
  10
  11 struct B {
  12   union {
  13     struct {
  14       int n = 5;
  15       int m;
  16     };
  17   };
  18 };
  19 const B b; // expected-error {{default initialization of an object of const type 'const B' without a user-provided default constructor}}
  20
  21 struct S {
  22   int i;
  23   int j;
  24 };
  25
  26 struct T {
  27   T() = default;
  28 };
  29
  30 struct C {
  31   union {
  32     S s;
  33   };
  34 };
  35
  36 struct D {
  37   union {
  38     T s;
  39   };
  40 };
  41
  42 const C c; // expected-error {{default initialization of an object of const type 'const C' without a user-provided default constructor}}
  43 const D d; // expected-error {{default initialization of an object of const type 'const D' without a user-provided default constructor}}
  44
  45 struct E {
  46   union {
  47     int n;
  48     int m=0;
  49   };
  50 };
  51 const E e;