gcc/testsuite/g++.dg/lookup/pr87269.C

// { dg-do compile { target c++11 } }
// PR c++/87269 ICE failing to keep a lookup

namespace std {
  typedef decltype (sizeof (0)) size_t;
}

namespace {
  void  operator"" _a (const char *, std::size_t) {}
}

void operator"" _a (unsigned long long);

template <typename> void f () { ""_a; }

void frob ()
{
  f<int> ();
}