GitHub works great for it, for diagnostic tickets in particular you can file them at https://github.com/rust-lang/rust/issues/new?assignees=&labels=A-diagnostic

GitHub works great for it, for diagnostic tickets in particular you can file them at https://github.com/rust-lang/rust/issues/new?assignees=&labels=A-diagnostics%2CT-compiler&template=diagnostics.yaml https://github.com/rust-lang/rust/issues/new?assignees=&labe... Even if it is an "it hurts when I do this" without more context it can be useful to bring the problem to our attention (but the more context you provide the higher the change we'll fix the problem).