Issue Description:

func failingFunc() {
    enum TestError {
        case connectivity(url: URL, void: Void)
    }
    let url = URL(string: "https://google.com")!
    let testError = TestError.connectivity(url: url, void: ())


    switch testError {
    case let .connectivity(value) where false:
        break
    case .connectivity:
        break
    }
}

failingFunc()

Reproduce rate is 100%.

Running this function will result in EXC_BAD_INSTRUCTION. Enabled zombies print following:

-[CFURL release]: message sent to deallocated instance 0x6000014e3330

The problem arises, when we have a case in enum with 2 or more associated values and one of them is URL or URLRequest (could not reproduce with other types). Also, we must have at least two same cases in switch which will be executed (changing `where false` to `where true` will not result in crash), and we have to refer to associated values as a tuple `let .connectivity(value)`, not separate values `let .connectivity(url, void)`.

Running this func in Xcode 10.1 results in no crash.