diff --git a/casbin/rbac/default_role_manager/role_manager.py b/casbin/rbac/default_role_manager/role_manager.py
index 5ea0605b..038f1cdf 100644
--- a/casbin/rbac/default_role_manager/role_manager.py
+++ b/casbin/rbac/default_role_manager/role_manager.py
@@ -133,7 +133,7 @@ def _matching_roles(self, name, match_order=MatchOrder.STR_PATTERN):
     def _get_role(self, name):
         if name not in self.all_roles:
             role = Role(name)
-            if self.matching_func != None:
+            if self.matching_func is not None:
                 for pattern_role in self._matching_roles(name):
                     role.copy_from(pattern_role)
             self.all_roles[name] = role
@@ -158,7 +158,7 @@ def add_link(self, name1, name2, *domain):
 
         user.add_role(role)
 
-        if self.matching_func != None:
+        if self.matching_func is not None:
             for r in self.all_roles.values():
                 if r.name != user.name and self._matching_fn(user.name, r.name, MatchOrder.PATTERN_STR):
                     r.add_role(role)
@@ -174,11 +174,12 @@ def delete_link(self, name1, name2, *domain):
         role = self._get_role(name2)
         user.remove_role(role)
 
-        for r in self.all_roles.values():
-            if r.name != user.name and self._matching_fn(user.name, r.name, MatchOrder.PATTERN_STR):
-                r.remove_role(role)
-            if r.name != role.name and self._matching_fn(role.name, r.name, MatchOrder.PATTERN_STR):
-                role.remove_role(r)
+        if self.matching_func is not None:
+            for r in self.all_roles.values():
+                if r.name != user.name and self._matching_fn(user.name, r.name, MatchOrder.PATTERN_STR):
+                    r.remove_role(role)
+                if r.name != role.name and self._matching_fn(role.name, r.name, MatchOrder.PATTERN_STR):
+                    role.remove_role(r)
 
     def has_link(self, name1, name2, *domain):
         user = self._get_role(name1)
@@ -255,7 +256,7 @@ def _get_role_manager(self, *domain):
         domain1 = self._get_domain(*domain)
         domain_links = self.all_links.get(domain1, [])
 
-        if self.domain_matching_func != None:
+        if self.domain_matching_func is not None:
             for domain2, links in self.all_links.items():
                 if domain1 != domain2 and match_error_handler(self.domain_matching_func, domain1, domain2):
                     domain_links = domain_links + links
@@ -313,7 +314,7 @@ def _get_role_manager(self, *domain):
     def _affected_role_managers(self, *domain):
         domain_pattern = self._get_domain(*domain)
 
-        if self.domain_matching_func != None:
+        if self.domain_matching_func is not None:
             return [
                 self.rm_map[domain_str]
                 for domain_str in self.rm_map.keys()
diff --git a/tests/rbac/test_role_manager.py b/tests/rbac/test_role_manager.py
index 40c2c1f0..e9ee2c3a 100644
--- a/tests/rbac/test_role_manager.py
+++ b/tests/rbac/test_role_manager.py
@@ -14,7 +14,7 @@
 
 from unittest import TestCase
 from casbin.rbac import default_role_manager
-from casbin.util import regex_match_func
+from casbin.util import key_match, regex_match_func
 import time
 from concurrent.futures import ThreadPoolExecutor
 import re
@@ -261,6 +261,23 @@ def test_has_link(role):
         for future in futures:
             self.assertTrue(future.result())
 
+    def test_delete_link_without_matching_func(self):
+        rm = self.get_role_manager()
+        rm.add_matching_func(None)
+        rm.add_link("u*", "g1")
+        rm.add_link("u1", "g2")
+        rm.add_link("g1", "g*")
+        self.assertFalse(rm.has_link("u1", "g1"))
+
+        rm.delete_link("u*", "g1")
+
+        self.assertFalse(rm.has_link("u*", "g1"))
+        self.assertFalse(rm.has_link("u*", "g*"))
+        self.assertTrue(rm.has_link("u1", "g2"))
+        self.assertTrue(rm.has_link("g1", "g*"))
+        self.assertEqual(rm.get_roles("u*"), [])
+        self.assertEqual(rm.get_users("g1"), [])
+
 
 class TestDomainManager(TestRoleManager):
     def get_role_manager(self):
@@ -313,3 +330,20 @@ def test_domain_role(self):
         self.assertTrue(rm.has_link("alice", "users", "domain1"))
         self.assertTrue(rm.has_link("alice", "user", "domain2"))
         self.assertFalse(rm.has_link("alice", "users", "domain2"))
+
+    def test_delete_link_without_matching_func_across_domains(self):
+        rm = self.get_role_manager()
+        rm.add_matching_func(None)
+        rm.add_domain_matching_func(key_match)
+        rm.add_link("alice", "admin", "*")
+        rm.add_link("bob", "admin", "*")
+        domains = ["d1", "d2", "d3"]
+        for d in domains:
+            self.assertTrue(rm.has_link("alice", "admin", d))
+
+        rm.delete_link("alice", "admin", "*")
+
+        for d in domains:
+            self.assertFalse(rm.has_link("alice", "admin", d))
+            self.assertTrue(rm.has_link("bob", "admin", d))
+        self.assertFalse(rm.has_link("alice", "admin", "d4"))