[Bug c++/82171] Cant use std::declval in concept testing map operator[]

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82171

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-09-14
     Ever confirmed|0                           |1

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Daniel Krügler from comment #2)
> As I understand it, this wording should allow using std::declval within the
> requirement-body as you did it without causing it being considered odr-used,
> so the current behaviour looks like a bug to me.

Let's go with that.