[Bug c++/60168] New: Incorrect check in ~unique_ptr() when Deleter::pointer type is not a pointer type

[ashish.sadanandan at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60168

            Bug ID: 60168
           Summary: Incorrect check in ~unique_ptr() when Deleter::pointer
                    type is not a pointer type
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ashish.sadanandan at gmail dot com

The following compiles on both VS2013 and ICC 13.0.1

#include <memory>

struct del
{
    using pointer = int;
    void operator()(int) {}
};

int main()
{
    std::unique_ptr<int, del> p;
}

It fails on gcc4.8.1 with this error

/usr/include/c++/4.8/bits/unique_ptr.h: In instantiation of
'std::unique_ptr<_Tp, _Dp>::~unique_ptr() [with _Tp = int; _Dp = del]':

main.cpp:13:35:   required from here

/usr/include/c++/4.8/bits/unique_ptr.h:183:12: error: invalid operands of types
'int' and 'std::nullptr_t' to binary 'operator!='

  if (__ptr != nullptr)

I believe that last if statement should be

    if (__ptr != pointer())