Sure. My point is that this is similar to what we guarantee: the compiler used to compile some code, and now it won't. As they say, "It has therefore been disallowed in Go 1.4, which is a breaking change, although very few programs will be affected." Our breaking changes have been similar.

> methodonpointerotpointer is not a breaking change if you read the specs.

It's not a breaking change according to Go's definition of breaking changes, by which Rust hasn't had any breaking change either.

> Rust doesn't even have a formal language specification.

Neither does Go, the spec is not a formal specification (and the first phrase of the intro states that it's a reference manual).

Rust has rfcs, and many of the "breaking changes" are in places where the implementation didn't follow the RfC. Others were in things that were never intended to compile. Its effectively the same thing.