clang/test/SemaCXX/cxx20-warn-dangling-paren-list-agg-init.cpp

   1 // RUN: %clang_cc1 -verify -std=c++20 %s -fsyntax-only
   2
   3 namespace std {
   4 template <class T> struct remove_reference { typedef T type; };
   5 template <class T> struct remove_reference<T&> { typedef T type; };
   6 template <class T> struct remove_reference<T&&> { typedef T type; };
   7
   8 template <class T> typename remove_reference<T>::type &&move(T &&t);
   9 } // namespace std
  10
  11 // dcl.init 16.6.2.2
  12 struct A {
  13   int a;
  14   int&& r;
  15 };
  16
  17 int f();
  18 int n = 10;
  19
  20 A a1{1, f()}; // OK, lifetime is extended for direct-list-initialization
  21 // well-formed, but dangling reference
  22 A a2(1, f()); // expected-warning {{temporary whose address is used as value}}
  23 // well-formed, but dangling reference
  24 A a4(1.0, 1); // expected-warning {{temporary whose address is used as value}}
  25 A a5(1.0, std::move(n));  // OK
  26
  27
  28
  29 struct B {
  30   const int& r;
  31 };
  32 B test(int local) {
  33   return B(1); // expected-warning {{returning address}}
  34   return B(local); // expected-warning {{address of stack memory}}
  35 }
  36
  37 void f(B b);
  38 void test2(int local) {
  39   // No diagnostic on the following cases where both the aggregate object and
  40   // temporary end at the end of the full expression.
  41   f(B(1));
  42   f(B(local));
  43 }
  44
  45 // Test nested struct.
  46 struct C {
  47   B b;
  48 };
  49
  50 struct D {
  51   C c;
  52 };
  53
  54 C c1(B(
  55   1  // expected-warning {{temporary whose address is used as value}}
  56 ));
  57 D d1(C(B(
  58   1  // expected-warning {{temporary whose address is used as value}}
  59 )));