The fact that it's not necessary to explicitly state which interfaces are implemented by a type is a key design decision in Go. It's not going to change.

Every language decision has pluses and minuses. I think most Go programmers feel that this problem is fairly hypothetical because it doesn't seem to come up for most people in real code. But, you're right, it's possible for it to come up. Every language decision has minuses, including this one.

But the pluses outweigh the minuses, so this is not going to change. Sorry.