golang exception to rule “interface pointer can't implement interface”

Question

In golang.org's official FAQ, under pointers there is this quote: "The insight is that although a pointer to a concrete type can satisfy an interface, with one exception a pointer to an interface can never satisfy an interface"

Out of curiosity, what is that exception to the above rule? ie when can an interface pointer implement an interface?

Answer 1

Just below it says:

The one exception is that any value, even a pointer to an interface, can be assigned to a variable of empty interface type (interface{}). Even so, it's almost certainly a mistake if the value is a pointer to an interface; the result can be confusing.