Question

Is it legal to use decltype with virtual member function pointers?

The following generates an internal error (C1001) with VS2012.

struct C
{
    virtual void Foo() {}

    typedef decltype(&C::Foo) type;   //pointer
}

But this compiles fine:

struct C
{
    virtual void Foo() {}

    typedef decltype(C::Foo) type;   //not pointer
}

Is it a bug?

Answer 1

MSVC has multiple known issues with decltype to member function pointers; see also Using decltype with member function pointers

This is legal syntax; g++ is perfectly happy with it (http://ideone.com/sTZi6). There is nothing in the standard to restrict the operation of decltype on member functions.