Repro for Rust issue 91671.
Basically, i've been making edits following the strategies from my MCVE patterns blog post, and then using the check-mcve.sh script to confirm that the problem described in the issue persists, and if so, automatically commits the state. (I decided to start automatically commiting it, because I previously did the bad thing of making a lot of aggressive edits and then lost track of the last good state. So now I'm checkpointing aggressively.