Investigate edge cases of Aggregations used as an attribute

[bd82]

Should an aggregation without AltTypes:

• Raise an issue when used as an attribute? should it be unknown attribute error?
• if deprecated raise a deprecated warning when using as an attribute?
• Can there be namespace conflicts between aggregations/props/events/assosiations?
  • Is this possible namespace conflict depend on the altTypes prop?
  • TODO: examine api.json are all members in a single dictionary thus prevent the conflict?