libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // type_traits
  10
  11 // is_assignable
  12
  13 #include <type_traits>
  14 #include "test_macros.h"
  15
  16 struct A
  17 {
  18 };
  19
  20 struct B
  21 {
  22     void operator=(A);
  23 };
  24
  25 template <class T, class U>
  26 void test_is_assignable()
  27 {
  28     static_assert(( std::is_assignable<T, U>::value), "");
  29 #if TEST_STD_VER > 14
  30     static_assert(  std::is_assignable_v<T, U>, "");
  31 #endif
  32 }
  33
  34 template <class T, class U>
  35 void test_is_not_assignable()
  36 {
  37     static_assert((!std::is_assignable<T, U>::value), "");
  38 #if TEST_STD_VER > 14
  39     static_assert( !std::is_assignable_v<T, U>, "");
  40 #endif
  41 }
  42
  43 struct D;
  44
  45 #if TEST_STD_VER >= 11
  46 struct C
  47 {
  48     template <class U>
  49     D operator,(U&&);
  50 };
  51
  52 struct E
  53 {
  54     C operator=(int);
  55 };
  56 #endif
  57
  58 template <typename T>
  59 struct X { T t; };
  60
  61 int main(int, char**)
  62 {
  63     test_is_assignable<int&, int&> ();
  64     test_is_assignable<int&, int> ();
  65     test_is_assignable<int&, double> ();
  66     test_is_assignable<B, A> ();
  67     test_is_assignable<void*&, void*> ();
  68
  69 #if TEST_STD_VER >= 11
  70     test_is_assignable<E, int> ();
  71
  72     test_is_not_assignable<int, int&> ();
  73     test_is_not_assignable<int, int> ();
  74 #endif
  75     test_is_not_assignable<A, B> ();
  76     test_is_not_assignable<void, const void> ();
  77     test_is_not_assignable<const void, const void> ();
  78     test_is_not_assignable<int(), int> ();
  79
  80 //  pointer to incomplete template type
  81     test_is_assignable<X<D>*&, X<D>*> ();
  82
  83   return 0;
  84 }