Prevent crash on generic NamedTuple with unresolved typevar bound

Author: sterliakov

mypy/semanal_shared.py

@@ -364,6 +364,9 @@ class HasPlaceholders(BoolTypeQuery):
     def __init__(self) -> None:
         super().__init__(ANY_STRATEGY)
 
+    def visit_tuple_type(self, t: TupleType, /) -> bool:
+        return super().visit_tuple_type(t) or t.partial_fallback.accept(self)
+
     def visit_placeholder_type(self, t: PlaceholderType) -> bool:
         return True