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Replay seven past rustc bugs - #12
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rustc/regressions holds seven patches that each revert a merged fix on the pinned compiler: #122891, #130201, #138678, #143247, #82047, #144050 and #162910. EDITS=regressions rustc/edits.sh applies, checks and reverts them, writing docs/regressions/*.txt. docs/regressions.md has the results: mirth catches five, the selected rustc tests none (the tests each fix added are outside the selection), and three of the five needed something added knowing the bug. check.sh gains two steps: P5 for two builds with -Zthreads=8, and an incremental rebuild after touching every source file, compared with tests/rmeta/<fixture>.touch.txt, which shows whether metadata was reused from the incremental cache. The normalisation replaces incremental session directory names. A failed build now prints why. The chain fixture gets an async closure called by value downstream, a trait returning impl Trait, a #[no_mangle] function, and a doc comment with unused reference definitions; the lists are blessed again. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_018Mnrg9JXj9X1ht6Qkz2ybh
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Stacked on #11.
The edits in
results.mdwere written by someone who knew what mirth watches. This PR tests it on real bugs instead. Each merged fix is reverted on the pinned compiler, the compiler is rebuilt, andcheck.sh chainplus the same rustc suites are run. The write-up isdocs/regressions.md..rmetanot removed before renameno_mangle/link_sectionnot encoded for rustdocDefPathHashMaporder under-ZthreadsHow to read this:
check.shstep: an incremental rebuild aftertouch, with its record blessed;metadata-stub-incremental-reuseruns the reuse path and still passes under #143247. It checks that the build works, not that the metadata was reused.parallel-reproducible-buildtest also passes with the revert.Changes:
rustc/regressions/*.patch: seven reverts, each generated from the pristine pinned source.rustc/edits.sh:EDITS=regressionsselects the patches.check.sh: two new steps, P5 with-Zthreads=8and the touch rebuild (tests/rmeta/<fixture>.touch.txt). A build that fails now prints why.🤖 Generated with Claude Code
https://claude.ai/code/session_018Mnrg9JXj9X1ht6Qkz2ybh