leanprover / leanprover/lean4

Windows Lean (4.18.0-pre, x86_64-w64-windows-gnu, commit c7f706baebc2, Release) segfaults when building stage2 compiler

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bug P-low
Dominant language
Lean
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Description

Description

make -j7 stage2 crashes with [/D/sources2/LEAN/lean4/build/release/stage2/bin/../share/lean/lean.mk:78: ../build/release/stage2/lib/lean/Std/Data/DTreeMap/Internal/Lemmas.olean] Segmentation fault

Context

The crash is reliably reproducible, in fact I encountered it when I was making my own modified custom Lean build.

I thought it was my fault, but after a thorough investigation I couldn't find any issues on my side, then ran the corresponding nightly (2025-02-25, immediately before stage0 update) on that file, caught the same segfault, finally decided to make an "official" Windows Lean build and caught the segfault again.

Lean version: 4.18.0-pre, x86_64-w64-windows-gnu, commit c7f706baebc2, Release.
OS version: MINGW64_NT-10.0-26100.

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the failure with make -j7 stage2 on the reported MINGW64 Windows environment, focusing on the stage2 target and Std/Data/DTreeMap/Internal/Lemmas.olean. Compare the reported release commit and nightly behavior; done means the stage2 compiler build completes without a segmentation fault.

Written by the indexing model from the issue text.

Assessment

Domain
build-system, compilers, operating-systems
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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