Rust 1.97.0

Rust 1.97.0 just shipped — and it is packed with polish, platform updates, and powerful new primitives for the integer set.

Language Lift

• Must-Use Smarter — Result<T, Uninhabited> and ControlFlow<Uninhabited, T> now count as equivalent to T for must-use lint purposes, eliminating false positives in generic code.
• Dead Code Detective — New allow-by-default dead_code_pub_in_binary lint catches unused pub items specifically in binary crates, keeping library boundaries clean.
• Trailing Self — Trailing self in imports now works in more scenarios, making use statements more intuitive and reducing friction when reorganizing modules.

Platform Push

• Target Features Stabilized — div32, lam-bh, lamcas, ld-seq-sa, and scq target features are now stable for use in cfg! and target_feature attributes.
• Atomic Alignment — cfg(target_has_atomic_primitive_alignment) enables conditional compilation based on atomic alignment guarantees for more portable low-level code.
• CUDA Cleanup — The nvptx64-nvidia-cuda target drops support for old architectures and old ISAs, streamlining the maintainability of the NVPTX backend.

Stabilized API Stack

• Default for RepeatN — Iterator repeat helper now implements Default.
• Copy for ffi::FromBytesUntilNulError — Error type gains Copy semantics for ergonomic error handling.
• Send for File on UEFI — File handles are now Send on UEFI targets.
• Integer Bit Gymnastics — isolate_highest_one, isolate_lowest_one, highest_one, lowest_one, and bit_width land on all integer types for direct bit-manipulation without external crates.

Upgrade when you are ready — but with no major breaking changes and a hefty batch of stabilizations, there is little reason to wait. Run rustup update stable and get 1.97.0 today.