[Bug libstdc++/70564] Problem with std::experimental::not_fn

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70564

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2016-04-07
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Rodrigo from comment #0)
> which calls _Not_fn<PRED>(_Not_fn<PRED>&) since __pred is an lvalue.
> However, between these _Not_fn constructors:
> 
>       template<typename _Fn2>
>         explicit
>         _Not_fn(_Fn2&& __fn) : _M_fn(std::forward<_Fn2>(__fn)) { }
> 
>         _Not_fn(const _Not_fn& __fn) = default;
>         _Not_fn(_Not_fn&& __fn) = default;
> 
> the first one wins and triggers an error.

Oops, that constructor needs to be constrained.