diff --git a/setools/mixins.py b/setools/mixins.py
index 37351fc..110a2d4 100644
--- a/setools/mixins.py
+++ b/setools/mixins.py
@@ -20,7 +20,7 @@
 # pylint: disable=attribute-defined-outside-init,no-member
 import re
 
-from .descriptors import CriteriaDescriptor, CriteriaSetDescriptor
+from .descriptors import CriteriaDescriptor, CriteriaSetDescriptor, CriteriaPermissionSetDescriptor
 from .util import match_in_set, match_regex, match_range, match_regex_or_set
 
 
@@ -193,7 +193,7 @@ class MatchPermission:
 
     """Mixin for matching an object's permissions."""
 
-    perms = CriteriaSetDescriptor("perms_regex")
+    perms = CriteriaPermissionSetDescriptor(name_regex="perms_regex")
     perms_equal = False
     perms_regex = False
     perms_subset = False
diff --git a/tests/commonquery.conf b/tests/commonquery.conf
index 735c95c..6781da9 100644
--- a/tests/commonquery.conf
+++ b/tests/commonquery.conf
@@ -1,4 +1,6 @@
 class infoflow
+class null
+class rw
 
 sid kernel
 sid security
@@ -63,6 +65,12 @@ common test12b
 class infoflow
 inherits test1
 
+class null
+inherits test10a
+
+class rw
+inherits test11a
+
 sensitivity low_s;
 sensitivity medium_s alias med;
 sensitivity high_s;