Calculate and set the type relation in each result building logic which
knows the actual result type.
CodeCompletionResultBuilder couldn't know the actual result type. From
the declaration alone, it cannot know the correct result type because it
doesn't know how the declaration is used (e.g. calling? referencing by
compound name? curried?)
Implement basic code completion support for #selector with property
getters/setters. The vast majority of this implementation comes from
Alex Hoppen (@ahoppen), with only a handful of my own tweaks. Alex has
more interesting ideas on improving this that I wasn't quite ready to
commit to, so this is more basic than the overall goal.
When we're code completing a postfix or dot expression inside the
subexpression of an #selector expression, prefer compound function
names. This helps us write, e.g.,
#selector(UIView.
and get completions such as "insertSubview(_:aboveSubview:)". Fixes
rdar://problem/24470075.
