modify typeshed instead of hacking calculate_mro

Author: tyralla

mypy/mro.py

@@ -15,11 +15,8 @@ def calculate_mro(info: TypeInfo, obj_type: Callable[[], Instance] | None = None
     mro = linearize_hierarchy(info, obj_type)
     assert mro, f"Could not produce a MRO at all for {info}"
     info.mro = mro
-    # The property of falling back to Any is (usually) inherited.
-    if info.fullname == "builtins._NotImplementedType":
-        info.fallback_to_any = False
-    else:
-        info.fallback_to_any = any(baseinfo.fallback_to_any for baseinfo in info.mro)
+    # The property of falling back to Any is inherited.
+    info.fallback_to_any = any(baseinfo.fallback_to_any for baseinfo in info.mro)
 
     type_state.reset_all_subtype_caches_for(info)
 

mypy/typeshed/stdlib/builtins.pyi

@@ -1269,7 +1269,7 @@ class property:
 
 @final
 @type_check_only
-class _NotImplementedType(Any):
+class _NotImplementedType:
     __call__: None
 
 NotImplemented: _NotImplementedType

test-data/unit/fixtures/notimplemented.pyi

@@ -13,7 +13,7 @@ class tuple: pass
 class dict: pass
 class classmethod: pass
 
-class _NotImplementedType(Any):
+class _NotImplementedType:
     __call__: NotImplemented  # type: ignore
 NotImplemented: _NotImplementedType