swift234

Sema: Fix getTypeOfMemberReference() for unbound instance methods

Always rewrite the Self type to the base type. Previously we only
did it if the method had a dynamic self return. This caused some
confusing behavior in this case:

class C {
  func m1() {}
  func m2() -> Self {}
}
class D : C {}

The types of D.m1 and D.m2 are:
- D.m1: C -> () -> ()
- D.m2: D -> () -> D

For protocols, this also meant that the type of an instance method
reference P.f had an open existential that could "leak out" of
the OpenExistentialExpr. Now, P.f will have type P -> ... -> ...,
however using such a reference still crashes, just in SILGen
instead of Sema, because we don't generate the right thunks yet.

Progress on <rdar://problem/21289579>.

Swift SVN r29447