swift234

Improve overload resolution for dynamic lookups.

Unlike normal overload resolution, where we always want the
most-specialized, overriding result, overload resolution for dynamic
lookups favors results in superclasses to those in subclasses, because
we want to put the least requirements on the object
type. Additionally, we don't allow overload resolution to select among
results that come from different classes or protocols.



Swift SVN r7743