swift234

Use the archetype for unqualified lookup within protocols and extensions thereof.

When performing unqualified lookup within a type context (or method
thereof) that is a protocol or a protocol extension, use the Self
archetype of the protocol or extension so we look in types implied by
the requirements as well. Part of rdar://problem/20509152, fixing the
example provided in rdar://problem/20694545.

Swift SVN r28363