Stream: bugs

Topic: Panic crash due to problems in type inference

Matthieu Pizenberg (Dec 13 2025 at 18:19):

When trying to access elements of a list with the type of the index inferred, the program panic crashes.

main! = || {
    list = [""]
    #indices : List(U64) # <- does not crash with this type annotation
    indices = [0]
    for i in indices {
        _x = List.get(list, i)
    }
}

I’ve opened an issue for this: https://github.com/roc-lang/roc/issues/8666

Last updated: Dec 21 2025 at 12:15 UTC