swift

70c7b5c9 - SILGen: Fix order of operations when invoking a mutating method on an existential that returns Self.

SILGen: Fix order of operations when invoking a mutating method on an existential that returns Self. 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.