diff --git a/scripts/qapi.py b/scripts/qapi.py
index 8edfd79..7dec611 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -940,7 +940,9 @@
         self.members = None
 
     def check(self, schema):
-        assert self.members is not False        # not running in cycles
+        if self.members is False:               # check for cycles
+            raise QAPIExprError(self.info,
+                                "Object %s contains itself" % self.name)
         if self.members:
             return
         self.members = False                    # mark as being checked
diff --git a/tests/Makefile b/tests/Makefile
index 69cef77..053c1ae 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -257,6 +257,8 @@
 qapi-schema += bad-type-bool.json
 qapi-schema += bad-type-dict.json
 qapi-schema += bad-type-int.json
+qapi-schema += base-cycle-direct.json
+qapi-schema += base-cycle-indirect.json
 qapi-schema += command-int.json
 qapi-schema += comments.json
 qapi-schema += double-data.json
diff --git a/tests/qapi-schema/base-cycle-direct.err b/tests/qapi-schema/base-cycle-direct.err
new file mode 100644
index 0000000..9c68f65
--- /dev/null
+++ b/tests/qapi-schema/base-cycle-direct.err
@@ -0,0 +1 @@
+tests/qapi-schema/base-cycle-direct.json:2: Object Loopy contains itself
diff --git a/tests/qapi-schema/base-cycle-direct.exit b/tests/qapi-schema/base-cycle-direct.exit
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/tests/qapi-schema/base-cycle-direct.exit
@@ -0,0 +1 @@
+1
diff --git a/tests/qapi-schema/base-cycle-direct.json b/tests/qapi-schema/base-cycle-direct.json
new file mode 100644
index 0000000..4fc66d0
--- /dev/null
+++ b/tests/qapi-schema/base-cycle-direct.json
@@ -0,0 +1,2 @@
+# we reject a loop in base classes
+{ 'struct': 'Loopy', 'base': 'Loopy', 'data': {} }
diff --git a/tests/qapi-schema/base-cycle-direct.out b/tests/qapi-schema/base-cycle-direct.out
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/qapi-schema/base-cycle-direct.out
diff --git a/tests/qapi-schema/base-cycle-indirect.err b/tests/qapi-schema/base-cycle-indirect.err
new file mode 100644
index 0000000..fc92fe4
--- /dev/null
+++ b/tests/qapi-schema/base-cycle-indirect.err
@@ -0,0 +1 @@
+tests/qapi-schema/base-cycle-indirect.json:2: Object Base1 contains itself
diff --git a/tests/qapi-schema/base-cycle-indirect.exit b/tests/qapi-schema/base-cycle-indirect.exit
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/tests/qapi-schema/base-cycle-indirect.exit
@@ -0,0 +1 @@
+1
diff --git a/tests/qapi-schema/base-cycle-indirect.json b/tests/qapi-schema/base-cycle-indirect.json
new file mode 100644
index 0000000..2866772
--- /dev/null
+++ b/tests/qapi-schema/base-cycle-indirect.json
@@ -0,0 +1,3 @@
+# we reject a loop in base classes
+{ 'struct': 'Base1', 'base': 'Base2', 'data': {} }
+{ 'struct': 'Base2', 'base': 'Base1', 'data': {} }
diff --git a/tests/qapi-schema/base-cycle-indirect.out b/tests/qapi-schema/base-cycle-indirect.out
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/qapi-schema/base-cycle-indirect.out