[meta.member] Comments for `static_assert` failures are incorrect

[frederick-vs-ja]

Currently, the example reads:

struct A { int a; };                    // a standard-layout class
struct B { int b; };                    // a standard-layout class
struct C: public A, public B { };       // not a standard-layout class

static_assert( is_pointer_interconvertible_with_class( &C::b ) );
  // Succeeds because, despite its appearance, &C​::​b has type
  // “pointer to member of B of type int''.
static_assert( is_pointer_interconvertible_with_class<C>( &C::b ) );
  // Forces the use of class C, and fails.

static_assert( is_corresponding_member( &C::a, &C::b ) );
  // Succeeds because, despite its appearance, &C​::​a and &C​::​b have types
  // “pointer to member of A of type int'' and
  // “pointer to member of B of type int'', respectively.
static_assert( is_corresponding_member<C, C>( &C::a, &C::b ) );
  // Forces the use of class C, and fails.

However, the failures are because is_pointer_interconvertible_with_class<C>( &C::b ) and is_corresponding_member<C, C>( &C::a, &C::b ) are themselves ill-formed, not false results. In microsoft/STL#5730, it was noticed that given int A::* or int B::* argument values and manually specification of template arguments to C, the deduction failed despite that there can be implicit conversions.

I think we can fix the example by (demo)

-static_assert( is_pointer_interconvertible_with_class<C>( &C::b ) );
- // Forces the use of class C, and fails.
+static_assert( !is_pointer_interconvertible_with_class<C, int>( &C::b ) );
+ // Forces the use of class C, and the result is false.

-static_assert( is_corresponding_member<C, C>( &C::a, &C::b ) );
-  // Forces the use of class C, and fails.
+static_assert( !is_corresponding_member<C, C, int, int>( &C::a, &C::b ) );
+  // Forces the use of class C, and the result is false.

But I'm not sure whether this is desired. Also, do we want a CWG issue for this?