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
notion of a reference to a set of declarations. Introduce one derived
class, OverloadedDeclRefExpr, which covers the only case we currently
handle for overload resolution [*]: a direct (unqualified) reference
to an overloaded set of entities. Future subclasses should handle,
e.g., overloaded member references such as a.b or a.b.c.
[*] Ugly hacks for static methods notwithstanding
Swift SVN r1345
