If a protocol has a superclass constraint, the existential type can be
upcast to the class type given by the constraint. This wasn't implemented
in the function conversion code path, leading to a crash.
Fixes <https://bugs.swift.org/browse/SR-12018> / <rdar://problem/58861162>.
This just eliminates -enable-sil-ownership from all target-swift-frontend and
target-swift-emit-silgen RUN lines. Both of those now include
enable-sil-ownership in their expansion.
This is the last part of SILGen conditionalized on EnableSILOwnership being
set. It also (as you can tell from the diff) eliminates a bunch of code from the
tests.
rdar://29791263
Delay allocating the result buffer for an opened Self return until right before it's needed. When a mutating method is invoked on an existential, the Self type won't be opened until late, when the formal access to the mutable value begins. Fixes rdar://problem/43507711.
