When a `borrowing` or `consuming` parameter is captured by a closure,
we emit references to the binding within the closure as if it is non-implicitly
copyable, but we didn't mark the bindings inside the closure for move-only
checking to ensure the uses were correct, so improper consumes would go
undiagnosed and lead to assertion failures, compiler crashes, and/or
miscompiles. Fixes rdar://127382105
This fixes the `consuming` and `borrowing` keywords for some basic
cases. In particular, if a nontrivial struct contains a trivial 'let'
field, then this pass would result in invalid SIL types:
class C {}
struct BV {
let p: UnsafeRawPointer
let c: C
}
func getPointer(bv: consuming BV) -> UnsafeRawPointer {
return bv.p
}
Ultimately, this pass makes sense, but there is something strange
about the way move-only-ness propagates into fields of aggregates
which needs to be fixed first. Until then, other features are blocked
on basic support for these keywords.
Fixes rdar://122701694 (`consuming` keyword causes verification error on invalid SIL types)
