gcc/testsuite/g++.dg/cpp0x/sfinae47.C

   1 // Source: Comment 16 of PR51213
   2 // { dg-do compile { target c++11 } }
   3
   4 template <class T>
   5 T && declval();
   6
   7 template <class T>
   8 constexpr auto hasSize(int) -> decltype(declval<T&>().size(), bool())
   9 { return true; }
  10
  11 template <class T>
  12 constexpr bool hasSize(...)
  13 { return false; }
  14
  15 struct A
  16 {
  17   int size();
  18 };
  19
  20 struct B : private A
  21 {
  22 };
  23
  24 static_assert(hasSize<A>(0),  "A");
  25 static_assert(!hasSize<B>(0), "B");