RUSTFLAGS="-D warnings" cargo check -p irtt-rs --no-default-features --features client (or --features tui) warned on dead code: some format.rs helpers are only called from the client applet, others only from the TUI. Narrowly #[cfg(feature = "...")]-gate each to the applet that actually uses it instead of allowing the warning or introducing a new feature, and split the tests that exercised both groups to match.