QAPISchemaVariant's "variants" field is typed as
List[QAPISchemaVariant], where the typing for QAPISchemaVariant allows
its type field to be any QAPISchemaType.

However, QAPISchemaVariant expects that all of its variants contain the
narrower QAPISchemaObjectType. This relationship is enforced at runtime
in QAPISchemaVariants.check(). This relationship is not embedded in the
type system though, so QAPISchemaVariants.check_clash() needs to
re-assert this property in order to call
QAPISchemaVariant.type.check_clash().

Signed-off-by: John Snow <jsnow@redhat.com>
---
 scripts/qapi/schema.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index 7508e3a4fa6..4d153b216c0 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -723,7 +723,10 @@ def check(self, schema, seen):
     def check_clash(self, info, seen):
         for v in self.variants:
             # Reset seen map for each variant, since qapi names from one
-            # branch do not affect another branch
+            # branch do not affect another branch.
+            #
+            # v.type's typing is enforced in check() above.
+            assert isinstance(v.type, QAPISchemaObjectType)
             v.type.check_clash(info, dict(seen))
 
 
-- 
2.43.0