Types Array[?], Hash[?,?], and Optional[?] are not assignable to themselves

The TypeCalculator.assignable? method does not consider the types Array[?], Hash[?,?], and Optional[?] to be assignable to themselves.

This is an internal fix. The problem can not be reproduced from Puppet. The only way to reproduce the problem is to use internal Ruby methods.

QA

risk: low
probability: low
severity: low
test level: unit