Borrow Checker

Rust Accepted This Safe-Looking Code for 4,001 Days: Reproducing the Borrow-Checker Use-After-Free on Stable 1.99.0, Where the Fix Is 8 Lines and the Test-Suite Bill Is 38 Files

Issue #164250 landed on 2026-10-13: a struct's lifetime bounds can be bypassed by assigning through a covariant field, with no unsafe block anywhere. I bisected the …