Lean kernel

Assess

Tools

The trusted core type checker that validates Lean declarations.

Why it's here

Placed in Assess: 1 article(s) of evidence from 1 source(s), led by security coverage, with 1 in the last 30 days. Confidence 24%. Low accumulated evidence, so it defaults conservatively pending more signal.

Evidence (1)

8Hacker News·8/1/2026security
Lean kernel soundness bug #14576 fixed
A soundness bug in the Lean kernel was reported after an AI-assisted claim of a Collatz disproof exposed a flaw in nested inductive type handling. The Lean team shipped a fix quickly, added regression tests, and noted that independent checking still works when both the main kernel and the external checker are up to date. The issue affected only a metaprogramming path and is described as an implementation bug rather than a flaw in Lean's theory.