T-compiler Meeting Agenda 2025-09-04

This week short agenda due to RustConf 2025 conference.

Backport nominations

T-compiler beta / T-compiler stable

• :beta: “fix drop scope for super let bindings within if let” rust#145342
  • Authored by dianne
  • Voting Zulip topic
  • Merged just a few hours ago
  • Discussed previously here
  • Addresses this comment and this comment (issues A and B from this list)
• :beta: “When determining if a trait has no entries for the purposes of omitting vptrs from subtrait vtables, consider its transitive supertraits’ entries, instead of just its own entries.” rust#145807
  • Authored by zachs18
  • Voting Zulip topic, in favor.
  • Merged last week. Fixes P-critical #145752 stable regression (comment)
  • No stable nomination (we are ~2 weeks from the next release)
• :beta: “don’t apply temporary lifetime extension rules to non-extended super let” rust#145838
  • Authored by dianne, nominated by @_theemathas (comment)
  • Voting Zulip topic, mostly towards declining the backport
  • Intended to fix #145784, stable regression
  • Not merged yet, being tested against multiple crater runs
• No stable nominations for T-compiler this time.

T-types beta / T-types stable

• No beta nominations for T-types this time.
• No stable nominations for T-types this time.

P-critical

T-compiler

• “Cross linker lto error: conflict llvm version.” rust#145981
  • Fixed by revert #146133 (comment)
• “staticlib with lto=fat now includes compiler_builtins as llvm bitcode after rustup update” rust#146145
  • Also fixed by revert #146133
• “Miscomputation error on nightly starting with 2025-08-11” rust#146163
  • Upstream LLVM issue llvm-project#156849 (comment)

T-types

• No P-critical issues for T-types this time.

Next meeting’s agenda draft: hackmd link