I think this is the core of where people can have different perspectives here, since they'll have different definitions for when something "changes its meaning".
An f64 is a superset of a u32 (or an i32) just as "a u64 is a superset of a u32". Does that change its meaning? I don't know, and reasonable people can probably disagree on it. Someone used to javascript, where an f64 often serves as an i54, would probably say no.