[Bug c++/56373] -Wzero-as-null-pointer-constant: does not catch issues with smart pointers

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56373

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2013-02-18 12:07:49 UTC ---
The warning isn't issued when 0 converts to std::nullptr_t, only when it
converts to a pointer type.

struct shared_ptr
{
    shared_ptr(decltype(nullptr)) { }
    ~shared_ptr() { }
};

int main ()
{
  shared_ptr a = 0;
  shared_ptr b(0);
  shared_ptr c{0};
}


(In reply to comment #0)
> It's also a bit sad that only d is diagnosed as useless, although I do
> understand that the shared_ptr has a constructor and a destructor that use
> it.

It's necessary, because otherwise you get bogus warnings from ScopeGuard-style
RAII types.