Rust: Unsafe Boundaries and Batch Merges

The compiler team tightened checks around unsafe code and low-level ABIs today, landing fixes for extern "custom" function pointers, unsafe cell access, and target feature diagnostics, while eight separate rollup pull requests batched dozens of smaller merges through the pipeline.

Duration: PT2M46S

Episode overview

This episode is a short developer briefing from Rust.

It explains recent repository work in plain language.

  • Show: Rust
  • Published: 2026-07-26T13:05:58Z
  • Audio duration: PT2M46S

Transcript excerpt

This excerpt keeps the crawler page concise. Listen to the episode or use the RSS feed for the full update.

It's July 26th, 2026, and this is Rust.

Today's biggest signal: the compiler team is sharpening the edges around unsafe code and low-level interfaces, catching gaps that let incorrect code slip through silently.

Start with function pointers and custom ABIs. PR 159780 extends existing ABI checks to function pointer types, closing a gap where "extern custom" functions could be called incorrectly through a pointer rather than a direct call. That same PR removes the ability for these custom-ABI functions to return "never,"…

Second theme: diagnostic clarity. PR 159809, from Nicholas Nethercote, fixes error messages that referenced a nonexistent "target features" attribute -- the real attribute is "target feature" with parentheses. Small fix, but it's the kind of inconsistency that confuses anyone reading a compiler error. Similarly, PR…

Third, process: eight rollup PRs today -- from JonathanBrouwer, jhpratt, GuillaumeGomez, and chenyukang -- batched over twenty pull requests each through CI. That volume reflects a normal, healthy merge queue, not any single incident.

Worth noting: PR 138618 finally lands const pointer support in inline assembly's const operand, implementing an RFC that's…

Nearby episodes from Rust

  1. Rollup Traffic and Path Normalization Cleanup
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  3. C-Variadics Land, LTO Gets More Dials
  4. SIMD Cleanup and the Splat Mangling Fix Chain
  5. Compiler Internals Get a Deep Clean
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