“method requires pointer receiver” in Go Programming Language

Question

I just saw a presentation of the Go programming language and thought I\'d try to write a few lines. Everything worked fine until I tried to use an interface in this situation. H

Answer 1

Change it to: doSomething(&e). func (e *entity) inc() satisfies incer interface only for *entity type. There is no inc() for just entity type and that's what's you're passing to doSomething().

Answer 2

I think there is some confusion here. inc is a method of the type *entity, and not of the type entity (while you can call methods on values directly on pointers; you cannot generally call methods on pointers directly on values). What you may be confused about is why you could call e.inc(), instead of having to do (&e).inc(). This is a little-known special case documented at the bottom of the Calls section in the language specification, that says if x is addressable, and &x's method set contains m, then x.m() is shorthand for (&x).m(). This applies to this case because e is a variable, so it is addressable; but other expressions may not be addressable. I would recommend that you not use this shortcut, however, as it causes confusion; it makes you think that e conforms to the interface inter, while it does not.