[Bug libstdc++/59027] std::is_signed does not include check for is_arithmetic

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59027

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Marc Mutz from comment #0)
> 
>   template<typename _Tp,
>            bool = is_arithmetic<_Tp>::value>
                    ^^^^^^^^^^^^^^^^^^

>     struct __is_signed_helper
>     : public false_type { };
> 
>   template<typename _Tp>
>     struct __is_signed_helper<_Tp, true>
                                     ^^^^
>     : public integral_constant<bool, _Tp(-1) < _Tp(0)>
>     { };

This looks right to me.