Merge branch 'master' into fix-typeis-for-types-with-type-params-in-u…

…nions

mypy/subtypes.py

@@ -1931,6 +1931,8 @@ def restrict_subtype_away(t: Type, s: Type) -> Type:
                 if isinstance(get_proper_type(item), UnionType) or not covers_type(item, s)
             ]
         return UnionType.make_union(new_items)
+    elif isinstance(p_t, TypeVarType):
+        return p_t.copy_modified(upper_bound=restrict_subtype_away(p_t.upper_bound, s))
     elif covers_type(t, s):
         return UninhabitedType()
     else: