Why can I call a non-const member function pointer from a const method?

Question

A co-worker asked about some code like this that originally had templates in it.

I have removed the templates, but the core question remains: why does this compile O

Answer 1

You are calling foo on object, not on this.

Since object is declared as an X&, in a constant CX, it is actually an X& const (which is not the same as const X&) allowing you to call non const methods on it.