swift

d0624893 - SILGen: Don't reference external property descriptors for @backDeployed properties.

SILGen: Don't reference external property descriptors for @backDeployed properties. The property descriptors of `@backDeployed` properties aren't available on OSes prior to the "back deployed before" OS version, so the descriptors cannot be referenced by clients that may run against older versions of the library that defines the property. See https://github.com/apple/swift/pull/59214 for prior art. Resolves rdar://106517386