[Bug libstdc++/57283] missing typedefs in specialized std::mem_fn for member variables

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57283

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> ---
The standard is clear, the typedef is not required when wrapping a pointer to
member data, see [func.memfn]

You can use a lambda expression in C++11:

    [](const cls& c) { return !c.value; };

In C++14 you will be able to write a generic lambda to negate arbitrary
function objects, replacing std::not1 completely:

    [](auto f) { return !f(); };