This wiki entry will try to document the rationales behind some important language decisions besides what's included in the Go FAQ and Effective Go.
Reference: https://groups.google.com/forum/#!topic/golang-nuts/aqTwXHaSC_Y
Go doesn't allow receiver's base type to be pointer to avoid possible ambiguity. Suppose you have:
type T blah
type P *T
func (t *T) String() string { ... }
func (p P) String() string { ... }
var p P
Then the meaning of the expression (*p).String() is ambiguous, because it can refer to
both (*T).String and P.String.
Go doesn't allow receiver's base type to be interfaces, because interfaces already have methods. (TODO)