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2 points by akkartik 593 days ago | link | parent

Interesting. I haven't heard this one before.

The stable branch has this bug as well.

I'd compare how x-set-car! is implemented in the two versions. Current HEAD:


I suspect Racket's changed something in unsafe-set-mcar! during the move to Chez Scheme.

(Sorry I just saw this.)

2 points by rocketnia 550 days ago | link

There was a pull request by samth that fixed this on the main branch, though I guess no one's ever ported it to the stable branch:

Just after that, Racket introduced an easier way to fix this, `unsafe-set-immutable-car!`, specifically as a stable way to mutate the so-called immutable cons cells going forward. :) We should probably move to that.

I've opened an issue for it: