Observed arrival · 2026-10-14
Lean Bugs: a trust-focused bug corpus
A browsable catalog of bugs in the Lean theorem prover, organized around which verification guarantees they break.
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- For
- Lean theorem-prover users and kernel developers
- Worth noticing
- Entries distinguish kernel soundness, compiler soundness, completeness, and reporting-faithfulness failures across 25 listed cases.
Field notes
The index assigns each entry an ID, a concise failure description, a broken-guarantee label, and a status; many visible entries are marked fixed. The corpus also includes issues beyond proof-kernel logic, such as runtime object corruption and a discrepancy between a logical model and compiled code. The page says additions and corrections go through repository pull requests, with schema validation during the site build.
Observed signals
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Editorial observations of this landing page, not a rating.
○OpenPublic substance visible
✦PrettyNotable craft visible
●ProPolished or operationally mature
◎NicheUnusually specific use
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