Rust: Intrinsics Optimization and New Share Trait
The Rust compiler saw significant performance improvements with intrinsics no longer requiring materialized places, plus the addition of an unstable Share trait for clone-as-alias types. Ten pull requests were merged focusing on code generation optimization and API enhancements.
Duration: PT2M4S
Transcript
Good morning, this is your Rust development briefing for May 24th, 2026.
Ten pull requests were merged yesterday, led by significant compiler optimizations. Scott McMahon merged a substantial intrinsics improvement that eliminates unnecessary memory allocation for most intrinsics. Previously, even returning a constant from `size_of_val` required stack allocation. The changes affect 21 files across the code generation backends, moving all but 5 intrinsics in LLVM to return values directly rather than through materialized places.
P8L1 contributed the new unstable Share trait as part of the 2026 ergonomic ref-counting project goal. The trait provides a `share` method that defaults to cloning, with initial implementations for references, Arc, Rc, and MPSC channel types. This addition spans 20 files and introduces the `share_trait` feature gate.
Makai410 implemented a fast path optimization for `derive(PartialOrd)` when also deriving `Ord`. The change reduces generated code significantly, though it maintains the existing limitation where PartialOrd must be derived after Ord to take effect.
Guillaume Gomez fixed jump-to-definition link generation for primitive type associated methods in rustdoc, resolving inference failures by generating PrimitiveType representations and adjusting href generation logic.
Additional merges included a reborrow validation fix ensuring all struct fields are properly checked, improved float literal f32 fallback suggestions to avoid invalid syntax, debuginfo test compatibility updates for newer Apple LLDB versions, and documentation improvements adding "phi" as an alias for the golden ratio constants.
What's next: The Share trait development continues toward the ergonomic ref-counting goals, and intrinsics optimization work may expand to the remaining five cases.
That's your Rust briefing. Back tomorrow with more updates.