swift234

Same-type requirements for the nested types of equivalent types are inferred.

The archetype builder was improperly propagating the requirement
source of a same-type requirement down to the inferred same-type
requirements for the nested types, causing a huge number of redundant
same-type requirements to show up in the canonical generic signatures
used for mangling. Mark such same-type requirements as inferred, which
shrinks the mangled name of LazyCollectionType.flatten from 4844 bytes
to 358 bytes.

Fixes rdar://problem/22861623.

Swift SVN r32356