Filtered highlights from This Week in Rust 664:

• Rust is soliciting testing for restricting trait implementability and field mutability; the compiler also enabled Polonius on nightly and landed many solver, workspace, and compile-time improvements. LLVM 23 brought broad performance wins, though Polonius currently regresses performance by about 3%.
• Interesting project updates include fearless_simd 0.7 (64-bit integers, improved generics, SSE2, and a path to 1.0), vairedb 0.1 (a cloud-native distributed analytical database), and kache/kobe updates for debuggable restores, convergence, and cluster-lease hardening.
• Strong systems/security reading: formal verification work for BPF, typed conversations that make illegal agent dialogues unrepresentable, TLS handshake benchmarks across four crypto libraries, and a chip-agnostic bare-metal embedded Rust architecture.
• Other notable items: Rust SIMD on GPUs, a reality check on rewriting software in Rust, a universal hardware-in-the-loop HAL test suite, and Rust Coreutils rebuilding Unix foundations.

I skipped the web/UI and general-opinion links; the issue’s most relevant threads are compiler performance, formal verification, distributed systems, embedded Rust, and agent correctness.