[Bug libstdc++/92770] std::unordered_map<T, U> requires both T and U to be fully declared

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92770

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

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

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Not a bug.

(In reply to Raphael Kubo da Costa from comment #0)
> The excerpt above works fine with libc++ and MSVC's STL.

Implementations might accept it as an extension or by lucky accident, but the
standard says it's undefined:
http://eel.is/c++draft/requirements#res.on.functions-2.5

For our implementation accepting it is not possible.