swift234

Introduce an AST node (OverloadedMemberRefExpr) that represents dot
syntax when name lookup finds multiple candidates. Overload resolution
is then used to select the best candidate and map the overloaded
member reference expression down to DotSyntaxCallExpr or
DotSyntaxBaseIgnoredExpr, as appropriate.

This implements part of <rdar://problem/11071641>, so that simple
overload resolution works, but there is still a bit of cleanup to do.



Swift SVN r1366