swift234

When building archetypes, gather all of the archetypes (both primary
and derived) so they can be stored within the generic parameter list
for use 'later'.

More immediately, when we deduce arguments for a polymorphic function
type, check that all of the derived archetypes conform to all of the
protocol requirements, stashing that protocol-conformance information
in the coercion context (also for use 'later'). From a type-checking
perspective, we now actually verify requirements on associated types
such as the requirement on R.Element in, e.g.,

  func minElement<R : Range requires R.Element : Ordered>(range : R)
         -> R.Element



Swift SVN r2460