SOQL does not support joining over plural attributes

[ledsoft]

SOQL fails with an assertion exception when attempting to do a join over a plural attribute, e.g.,

SELECT a FROM TypeA a WHERE a.pluralAttribute.age > 18

Where pluralAttribute is a plural attribute.

This is apparently because it expects the attribute for join to be always singular. The same issue applies to Criteria API.

[ledsoft]

Update: Criteria API has a different issue, but eventually it would end up with the same error. So both SOQL and Criteria API need fixing.