"Simplify member access" not offered after cast expression to function pointer type

[jhinder]

Version Used: VS 18.0.0 Insiders

Steps to Reproduce:
Open the lightbulb menu at the marked locations.

unsafe class C
{
    static void M1()
    {
        delegate*<void> d = &C.M1;
        d();
    }

    static void M2()
    {
        var d = (delegate*<void>)(&C.M2);
        d();
    }
}

Expected Behavior:
"Simplify member access" is offered at both locations, simplifying the expression to M1 and M2, respectively.

Actual Behavior:
For the reference to C.M1, the refactoring is offered and the expression can be simplified (the "C" identifier is also greyed out to indicate a possible simplification).
For the reference to C.M2, the refactoring is not offered (even though it can be simplified) and the "C" identifier is not greyed out.