Inherited entities and compundIndex

[thom-ek]

There is a crash during conversion of compoundIndex created on child entity which contains attributes from parent entity.

It crashes there: [currentCompoundIndex addObject:compoundIndexProperty];
line 92 @ NSEntityDescription+momcom.m

and crash look just this:
Caught: NSInvalidArgumentException: *** -[__NSArrayM insertObject:atIndex:]: object cannot be nil

There should be a message that indexes on inherited attributes are not supported.