swift234

Rework our approach to deduction of generic parameters during overload
resolution. When we see a polymorphic function type, we substitute
"deducible generic parameter" types for each of the generic
parameters. Coercion then deduces those deducible generic parameter
types. This approach eliminates the confusion between the types used
in the definition (which must not be coerced) and the types used when
the generic function is referenced (which need to be coerced).

Note that there are still some terrible inefficiencies in our handling
of these types.



Swift SVN r2297