[ChadNauseam]

My interpretation of the post is that the rule is deeper than that. This is the most important part:

> Here is the most famous implication of this rule: Rust does not infer function signatures. If it did, changing the body of the function would change its signature. While this is convenient in the small, it has massive ramifications.

Many languages violate this. As another commenter mentioned, C++ templates are one example. Rust even violates it a little - lifetime variance is inferred, not explicitly stated.

[fpoling]

Lifetimes for a function signature in Rust are never inferred from the function code. Rather Rust has implicit lifetime specs with straightforward rules to recover the explicit full signature.

[ChadNauseam]

I was speaking about variance specifically. They are not inferred from function bodies, but I think it's fair to say that it's a soft violation of the golden rule because variance has a lot of spooky action at a distance (changing a struct definition can change its variance requirements, which then has ripple effects over all type signatures that mention that struct)