One of the PITA aspects of this type of break is when library writers need to change (via hard break) their external APIs because Rust has made a "minor break that can be easily fixed".

For example, one of the timely traits had `min` and `max` methods, as it corresponded to a type with upper and lower bounds. Rust added `min` and `max` convenience methods to all implementors of `Ord` (which this type was), which now means that anyone who wants to use the type needs to use UFCS. Or, I issue a major break so that their lives don't suck (now `minimum` and `maximum`).

The Rust change was classified as fixing a "papercut", so that folks wouldn't have to `use std::cmp::{min, max};`, but it's a pain in the arse when it's done so casually.