Fixes #278. The approach here is different from what we thought before. According to this commit, there are three valid forms of Mapping[K, V].get(): d.get() # returns Optional[V] d.get(None) # also returns Optional[V] (seen in the wild) d.get(v) # requires v to have type V, and returns V So we don't allow d.get(d) where d is a type unrelated to V. This is a compromise, but I don't think there's much use for d.get(d) with a default that is differently-typed than V, and when I tried it my application code (that didn't use this) wouldn't type-check correctly.

Commits

Commits on Sep 15, 2016

Better signature for Mapping.get().