@swift-main
import Foundation struct LoggedInState {} struct LoggedOutState {} let date1 = Date() let date2 = Date() enum Permission: Equatable { case freeDuring(Range<Date>) case free case subscriberOnly } print(enumTag(Permission.freeDuring(date1 ..< date2))) print(enumTag(Permission.free)) print(enumTag(Permission.subscriberOnly)) private func enumTag<Case>(_ `case`: Case) -> UInt32? { let metadataPtr = unsafeBitCast( type(of: `case`), to: UnsafeRawPointer.self ) let kind = metadataPtr.load(as: Int.self) let isEnumOrOptional = kind == 0x201 || kind == 0x202 guard isEnumOrOptional else { return nil } let vwtPtr = (metadataPtr - MemoryLayout<UnsafeRawPointer>.size) .load(as: UnsafeRawPointer.self) let vwt = vwtPtr.load(as: EnumValueWitnessTable.self) return withUnsafePointer(to: `case`) { vwt.getEnumTag($0, metadataPtr) } } private struct EnumValueWitnessTable { let f1, f2, f3, f4, f5, f6, f7, f8: UnsafeRawPointer let f9, f10: Int let f11, f12: UInt32 let getEnumTag: @convention(c) (UnsafeRawPointer, UnsafeRawPointer) -> UInt32 let f13, f14: UnsafeRawPointer }
(edited)