swift234

For nested archetypes, track the corresponding associated type.

Each nested archetype X.Y corresponds to an associated type named 'Y'
within one of the protocols to which X conforms. Record the associated
type within the archetype itself. When performing type substitutions,
use that associated type to extract the corresponding type witness
rather than looking for the type itself. This is technically more
correct (since we used the type witness for type checking), and a step
toward pulling type substitutions into the AST.



Swift SVN r7624