The output of the class class method argument (overload using the const constructor) fails with returning the return type to gcc, but not to clang

Question

Nothing more clear than the old good MCVE:

struct X { auto get(int) const -> int { return {}; } auto get(int) -> int { return {}; } }; template <class R> auto f(auto (X::*)(int) const -> R) {} // ^~~~ ~~~~ // trailing return type int main() { f(&X::get); } 

This does not work in g ++ (4.9.2 and 5.1.0). However, if the old return type is used:

 template <class R> auto f(R (X::*)(int) const) {} // ^ // old return type 

it works.

In clang (3.5.0) both options work.

I know that the return type of the return type changes when the type of the return value is output and its volume, so I will not quickly throw it as a gcc error. So what does the standard say? Which compiler is right?

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The most important error message, I think

Failed to output pattern parameter "R"

g ++ full post:

 main2.cpp: In function 'int main()': main2.cpp:21:12: error: no matching function for call to 'f(<unresolved overloaded function type>)' f(&X::get); ^ main2.cpp:18:25: note: candidate: template<class R, class auto:1> auto f(auto:1 (X::*)(int) const) template <class R> auto f(auto (X::*)(int) const -> R) {} ^ main2.cpp:18:25: note: template argument deduction/substitution failed: main2.cpp:21:12: note: types 'auto:1 (X::)(int) const' and 'int (X::)(int)' have incompatible cv-qualifiers f(&X::get); ^ main2.cpp:21:12: note: couldn't deduce template parameter 'R' <builtin>: recipe for target 'main2' failed make: *** [main2] Error 1