title: How to work around swift requirement that switch default statement has to be last (after cases)
body: <p>A typical code that used to work fine in all C variants
  but somehow is no longer good enough in the brave new world of swift:</p>
  <pre><code>@Environment(\.colorScheme) var colorScheme
  var body: some View
  {
      var multiplier: CGFloat
      switch(colorScheme)
      {
      @unknown default:
          assertionFailure()
          fallthrough
      case .light:
          multiplier = 0.3
      case .dark:
          multiplier = 0.1
          fallthrough
      }
  </code></pre>
  <p>How would I rewrite this in such a fashion that swift compiler won't complain about?</p>
  <p>As a stop gap measure I did</p>
  <pre><code>    switch(colorScheme)
      {
      case .light:
          multiplier = 0.3
      case .dark:
          multiplier = 0.1
      @unknown default:
          preconditionFailure()
      }
  </code></pre>
  <p>to satisfy the requirement that <code>default</code> comes last but this is
  obviously NOT the semantics that I want.</p>
  <p>I want the code to bomb in debug builds and fallback onto dark o light case in
  release cases so that the code works in the field.</p>