clang/test/SemaTemplate/argument-dependent-lookup.cpp

   1 // RUN: %clang_cc1 -std=c++14 -verify %s
   2 // RUN: %clang_cc1 -std=c++14 -verify %s -DHAVE_UNQUALIFIED_LOOKUP_RESULTS
   3 // expected-no-diagnostics
   4
   5 namespace address_of {
   6 #ifdef HAVE_UNQUALIFIED_LOOKUP_RESULTS
   7   struct Q {};
   8   void operator&(Q);
   9 #endif
  10
  11   template<typename T> struct A {
  12     static constexpr auto x = &T::value;
  13   };
  14
  15   template<typename T> struct B {
  16     constexpr int operator&() { return 123; }
  17   };
  18
  19   template<typename T> struct C {
  20     static_assert(sizeof(T) == 123, "");
  21   };
  22
  23   struct X1 {
  24     static B<X1> value;
  25   };
  26   struct X2 : B<X2> {
  27     enum E { value };
  28     friend constexpr int operator&(E) { return 123; }
  29   };
  30
  31   struct Y1 {
  32     C<int> *value;
  33   };
  34   struct Y2 {
  35     C<int> value();
  36   };
  37
  38   // ok, uses ADL to find operator&:
  39   static_assert(A<X1>::x == 123, "");
  40   static_assert(A<X2>::x == 123, "");
  41
  42   // ok, does not use ADL so does not instantiate C<T>:
  43   static_assert(A<Y1>::x == &Y1::value, "");
  44   static_assert(A<Y2>::x == &Y2::value, "");
  45 }