diff --git a/qemu/scripts/qapi.py b/qemu/scripts/qapi.py
index 224f0357..a35ee313 100644
--- a/qemu/scripts/qapi.py
+++ b/qemu/scripts/qapi.py
@@ -992,6 +992,7 @@ class QAPISchemaObjectType(QAPISchemaType):
         if self.variants:
             self.variants.check(schema, seen)
             assert self.variants.tag_member in self.members
+            self.variants.check_clash(schema, seen)
 
     def is_implicit(self):
         # See QAPISchema._make_implicit_object_type()
@@ -1056,6 +1057,19 @@ class QAPISchemaObjectTypeVariants(object):
         assert isinstance(self.tag_member.type, QAPISchemaEnumType)
         for v in self.variants:
             v.check(schema, self.tag_member.type)
+            if isinstance(v.type, QAPISchemaObjectType):
+                v.type.check(schema)
+
+    def check_clash(self, schema, seen):
+        for v in self.variants:
+            # Reset seen map for each variant, since qapi names from one
+            # branch do not affect another branch
+            vseen = dict(seen)
+            assert isinstance(v.type, QAPISchemaObjectType)
+            assert not v.type.variants       # not implemented
+            for m in v.type.members:
+                m.check_clash(vseen)
+
 
 class QAPISchemaObjectTypeVariant(QAPISchemaObjectTypeMember):
     def __init__(self, name, typ):