qapi: Factor out QAPISchemaObjectTypeMember.check_clash()

While there, stick in a TODO change key of seen from QAPI name to C
name.  Can't do it right away, because it would fail the assertion for
tests/qapi-schema/args-has-clash.json.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1446559499-26984-6-git-send-email-armbru@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1447836791-369-10-git-send-email-eblake@redhat.com>

scripts/qapi.py

@@ -984,12 +984,10 @@ def check(self, schema):
             assert not self.base.variants       # not implemented
             self.base.check(schema)
             for m in self.base.members:
-                assert m.name not in seen
-                seen[m.name] = m
+                m.check_clash(seen)
         for m in self.local_members:
             m.check(schema)
-            assert m.name not in seen
-            seen[m.name] = m
+            m.check_clash(seen)
         if self.variants:
             self.variants.check(schema, seen)
         self.members = seen.values()
@@ -1030,6 +1028,11 @@ def check(self, schema):
         self.type = schema.lookup_type(self._type_name)
         assert self.type
 
+    def check_clash(self, seen):
+        # TODO change key of seen from QAPI name to C name
+        assert self.name not in seen
+        seen[self.name] = self
+
 
 class QAPISchemaObjectTypeVariants(object):
     def __init__(self, tag_name, tag_member, variants):