Commits

Chris Lattner committed 7530f406fd5
Implement <rdar://problem/19290065> retains and releases of 'let' values aren't necessary teach SILGenLValue that let values guarantee the lifetime of their value for at least the duration of whatever expression references the let value. This allows us to eliminate retains/release pairs in a lot of cases, and provides more value for people to use let instead of var. This combines particularly well with +0 self arguments (currently just protocol/archetype dispatches, but perhaps someday soon all method dispatches). Thanks to John for suggesting this. Swift SVN r24004