[Runtime] Check for @objc existentials conforming to @objc protocols. #20217
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@swift-ci please smoke test and merge |
jrose-apple
reviewed
Nov 1, 2018
| case MetadataKind::Existential: { | ||
| #if SWIFT_OBJC_INTEROP | ||
| // If all protocols are @objc and at least one of them conforms to the | ||
| // protocol, succeed. |
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Hm. What about non-@objc protocols that inherit from @objc protocols?
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Only @objc existentials can conform to protocols. A non-@objc protocol does not, even if it inherits from an @objc protocol. For example, the type checker rightly rejects this:
@objc protocol P { }
protocol Q: P { }
struct X<T:P> { }
typealias Y = X<Q>There was a problem hiding this comment.
Oh, right, we aren't unboxing anything in this cast.
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When checking conformance requirements against an @objc protocol, also
check for an @objc existential using protocol_conformsToProtocol().
Fixes rdar://problem/45685649.