swift234

[Protocol conformances] Check when an existential type conforms to its protocol.

For a given protocol, check whether an existential of that protocol
type conforms to itself. We use an intentionally conservative
definition here that makes the existential not conform to the protocol
if the protocol contains:
  - any associated type, or
  - any requirement that refers to 'This' anywhere except the curried
  'this' parameter, or
  - inherits from any protocol for which either of the above hold.



Swift SVN r6613