1 // PR c++/81188 2 // { dg-do compile { target c++11 } } 3 4 template <class F> 5 struct C { 6 F fast(long i) const; 7 auto operator[](long i) const -> decltype(this->fast(i)); 8 }; 9 10 template <class F> 11 auto C<F>::operator[](long i) const -> decltype(this->fast(i)) { 12 return fast(i); 13 } 14