[Bug libstdc++/48113] [4.6/4.7 Regression] [C++0x] bind with tuple argument fails

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48113

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-03-14 16:22:44 UTC ---
Jason, could you take a look at this reduced testcase, which has no libstdc++
dependency?

template<typename T> T declval();

struct tuple { };

struct F1
{
    void operator()(tuple);
};

typedef void (*F2)(tuple);

template<typename F, typename T>
struct Bind
{
    decltype( F()(declval<T&>()) )
    f();

    decltype( F()(declval<volatile T&>()) )
    f() volatile;
};

int main()
{
    Bind<F1, tuple>().f();  // OK

    Bind<F2, tuple>().f();  // ERROR
}

This shows that SFINAE removes the Bind::f() volatile overload if F is a
functor, but not if it's a function pointer.  I can't see why it should be
different.

Is this a FE bug, or do I need to handle function pointers differently in
std::bind?  Thanks