[dureuill]

Yes, users can misuse warnings by ignoring them in CI, but the ergonomic cost of forcing unused variables as errors is disproportionate in regard to this. This affects all users regardless of if they would deny warnings in CI, and leads to either removing/adding some code repeatedly so it compiles at all, or worse adding fake uses, defeating the purpose of the warning. I am using C++ with -Werror during development because it is the only way to keep my sanity (functions not returning a value in C++ is a warning), but it is an ergonomic disaster that I am happy to avoid when using Rust (where the right place to deny warnings is in CI).

I would agree that forcing uninitialised variables as errors is a design mistake.