Semantics of an empty PermittedSubtypes attribute for the VM

[Remi Forax]

Hi all,
With my ASM hat,
from the JVMS POV, javac can not generate an empty list of permitted subtypes and the implementation in Hotspot ignores the attribute PermittedSubtypes if there is no subtype listed.

So currently, ASM doesn't allow you to create an attribute PermittedSubtypes with an empty number of subtypes.
I believe this is the correct semantics, i just want to be sure that i've not overlook something. 

regards,
Rémi