Rust 1.94.0: array_windows, Cargo Config Includes, and 10 Breaking Changes You Should Know About

Rust 1.94.0 landed on March 5, 2026. Three headline features and a surprisingly long compatibility notes section. Here's what actually matters if you're shipping Rust in production. The Headlines array_windows Finally Stabilized This one's been cooking since 2020. array_windows gives you sliding window iteration over slices, but with compile-time known sizes instead of runtime slices. // Old way: runtime-sized windows, manual indexing data .windows ( 4 ) .any (| w | w [ 0 ] != w [ 1 ] && w [ 0 ] == w [ 3 ] && w [ 1 ] == w [ 2 ]) // New way: destructure directly, compiler knows the size data .as_bytes () .array_windows () .any (|[ a1 , b1 , b2 , a2 ]| ( a1 != b1 ) && ( a1 == a2 ) && ( b1 == b2 )) The real win here isn't just ergonomics. The compiler can eliminate bounds checks entirely because it knows the window size at compile time. If you're doing any kind of signal processing, pattern matching, or rolling calculations over slices, this is a free performance upgrade. The window size