mypy

9be49b3b - Prevent crashing when `match` arms use name of existing callable (#18449)

Prevent crashing when `match` arms use name of existing callable (#18449) Fixes #16793. Fixes crash in #13666. Previously mypy considered that variables in match/case patterns must be Var's, causing a hard crash when a name of captured pattern clashes with a name of some existing function. This PR removes such assumption about Var and allows other nodes.