b71fc18abe
3387: Type inference for slice patterns r=flodiebold a=JoshMcguigan Fixes #3043 Notes to reviewer: 1. This only works if `expected` is `Ty::Apply`. I'm not sure of the implications of this. 1. This only works if the slice pattern only has a prefix. I think this means it doesn't work for subslice patterns, which are currently only available behind a feature flag. Co-authored-by: Josh Mcguigan <joshmcg88@gmail.com>