Since line info is remembered as QAPISchema.line now, this patch
uses it as additional info for every expr in QAPISchema inside qapi.py,
then improves error message with it in checking of exprs.

For common union the patch will check whether base is a valid complex
type if specified. For flat union it will check whether base presents,
whether discriminator is found in base, whether the key of every branch
is correct when discriminator is an enum type.
Signed-off-by: NWenchao Xia <wenchaoqemu@gmail.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

It is bad that same key was specified twice, especially when a union has
two branches with same condition. This patch can prevent it.
Signed-off-by: NWenchao Xia <wenchaoqemu@gmail.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Message-id: 1374939721-7876-6-git-send-email-armbru@redhat.com
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

The parser handles erroneous input badly.  To be improved shortly.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Message-id: 1374939721-7876-2-git-send-email-armbru@redhat.com
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>