qapi: Simplify QAPISchemaObjectTypeMember.check()

QAPISchemaObjectTypeMember.check() currently does four things:

1. Compute self.type

2. Accumulate members in all_members

   Only one caller cares: QAPISchemaObjectType.check() uses it to
   compute self.members.  The other callers pass a throw-away
   accumulator.

3. Accumulate a map from names to members in seen

   Only one caller cares: QAPISchemaObjectType.check() uses it to
   compute its local variable seen, for self.variants.check(), which
   uses it to compute self.variants.tag_member from
   self.variants.tag_name.  The other callers pass a throw-away
   accumulator.

4. Check for collisions

   This piggybacks on 3: before adding a new entry, we assert it's new.

   Only one caller cares: QAPISchemaObjectType.check() uses it to
   assert non-variant members don't clash.

Simplify QAPISchemaObjectType.check(): move 2.-4. to
QAPISchemaObjectType.check(), and drop parameters all_members and
seen.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-Id: <1446559499-26984-2-git-send-email-armbru@redhat.com>
[rebase to earlier changes that moved tag_member.check() of
alternate types, commit message typo fix]
Signed-off-by: NEric Blake <eblake@redhat.com>
Message-Id: <1447836791-369-6-git-send-email-eblake@redhat.com>

scripts/qapi.py

@@ -990,7 +990,10 @@ class QAPISchemaObjectType(QAPISchemaType):
             assert c_name(m.name) not in seen
             seen[m.name] = m
         for m in self.local_members:
-            m.check(schema, members, seen)
+            m.check(schema)
+            assert m.name not in seen
+            seen[m.name] = m
+            members.append(m)
         if self.variants:
             self.variants.check(schema, members, seen)
         self.members = members
@@ -1027,12 +1030,9 @@ class QAPISchemaObjectTypeMember(object):
         self.type = None
         self.optional = optional
 
-    def check(self, schema, all_members, seen):
-        assert self.name not in seen
+    def check(self, schema):
         self.type = schema.lookup_type(self._type_name)
         assert self.type
-        all_members.append(self)
-        seen[self.name] = self
 
 
 class QAPISchemaObjectTypeVariants(object):
@@ -1065,7 +1065,7 @@ class QAPISchemaObjectTypeVariant(QAPISchemaObjectTypeMember):
         QAPISchemaObjectTypeMember.__init__(self, name, typ, False)
 
     def check(self, schema, tag_type, seen):
-        QAPISchemaObjectTypeMember.check(self, schema, [], seen)
+        QAPISchemaObjectTypeMember.check(self, schema)
         assert self.name in tag_type.values
 
     # This function exists to support ugly simple union special cases
@@ -1087,7 +1087,7 @@ class QAPISchemaAlternateType(QAPISchemaType):
         self.variants = variants
 
     def check(self, schema):
-        self.variants.tag_member.check(schema, [], {})
+        self.variants.tag_member.check(schema)
         self.variants.check(schema, [], {})
 
     def json_type(self):