swift

80db0545 - [cxx-interop] Fix assertion failure from unavailable NS_ENUM typedef

[cxx-interop] Fix assertion failure from unavailable NS_ENUM typedef The NS_OPTIONS macro sometimes uses a pattern where it loosely associates a typedef with an anonymous enum via a shared underlying integer type (emphasis on "loosely"). The typedef is marked as unavailable in Swift so as to not cause name ambiguity when we associate the anonymous enum with said typedef. We use unavailability as a heuristic during the import process, but that conflates NS_OPTIONS with NS_ENUMs that can be marked as unavailable for entirely unrelated reasons. That in and of itself is fine, because the import logic is general enough to handle both cases, but we have an assertion that seems to be unaware of this scenario, and trips on unavailable NS_ENUMs. (In those cases, the typedef points to the enum rather than the underlying integer type.) This patch fixes the assertion to be resilient against such cases by looking through the enum a typedef refers to. rdar://150399978