If x.Foo() and y.Foo() do different things and return different values, clearly x != y, and golang needs some kind of SQL-style is-null check rather than using

If x.Foo() and y.Foo() do different things and return different values, clearly x != y, and golang needs some kind of SQL-style is-null check rather than using equality to check for null. But dynamic dispatch on "what type of object do I not have?" is still a damn weird thing to want.