[Bug c++/57794] using keyword for function alias doesn't work with plus suffix return type

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57794

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

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

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
It's not valid code, [] introduces a lambda expression, not a function type,
but a lambda expression must have a body.

Maybe you mean:

using to_lower_fn_ptr = auto (input_base_type, const std::locale&) ->
input_base_type;

which compiles fine.