Stackoverflow when type checking

[crides]

I was trying to find the maximum of all the indexed positions in a list of arrays, and I ended up with this (it doesn't type check; the data should be converted to list of streams first):

let { foldl } = import! std.foldable
let { max } = import! std.cmp
let stream @ { Stream, zip_with, ? } = import! std.stream

foldl (\acc x -> zip_with max (stream.of acc) (stream.of x)) [0] [[5], [3]]

This results in a stackoverflow for the type checker instead of giving an error. Since this is incorrect code anyway, there's no rush, but I hope this can help reveal some type checker bugs.