swift234

Implement two more pieces to the application of a constraint system to
an expression:
  - For references to polymorphic functions, use the opened type to
  produce substitutions and build the SpecializeExpr, rather than
  falling back to the 'unresolved type' hack. This makes application
  actually follow the results determined by the constraint solver so,
  e.g., the ternary operator function works.
  - For function expressions, fill in the determined (then simplified)
  types for each of the named, untyped arguments.
  



Swift SVN r2872