Refs #25466 -- Removed unused DeprecationInstanceCheck.

Unused since ff419de.

django/utils/deprecation.py

@@ -83,16 +83,6 @@ def __new__(cls, name, bases, attrs):
         return new_class
 
 
-class DeprecationInstanceCheck(type):
-    def __instancecheck__(self, instance):
-        warnings.warn(
-            "`%s` is deprecated, use `%s` instead." % (self.__name__, self.alternative),
-            self.deprecation_warning,
-            2,
-        )
-        return super().__instancecheck__(instance)
-
-
 class MiddlewareMixin:
     sync_capable = True
     async_capable = True

tests/deprecation/tests.py

@@ -1,12 +1,7 @@
 import warnings
 
 from django.test import SimpleTestCase
-from django.utils.deprecation import (
-    DeprecationInstanceCheck,
-    RemovedAfterNextVersionWarning,
-    RemovedInNextVersionWarning,
-    RenameMethodsBase,
-)
+from django.utils.deprecation import RemovedAfterNextVersionWarning, RenameMethodsBase
 
 
 class RenameManagerMethods(RenameMethodsBase):
@@ -166,14 +161,3 @@ def test_removedafternextversionwarning_pending(self):
         self.assertTrue(
             issubclass(RemovedAfterNextVersionWarning, PendingDeprecationWarning)
         )
-
-
-class DeprecationInstanceCheckTest(SimpleTestCase):
-    def test_warning(self):
-        class Manager(metaclass=DeprecationInstanceCheck):
-            alternative = "fake.path.Foo"
-            deprecation_warning = RemovedInNextVersionWarning
-
-        msg = "`Manager` is deprecated, use `fake.path.Foo` instead."
-        with self.assertWarnsMessage(RemovedInNextVersionWarning, msg):
-            isinstance(object, Manager)