SI-7239 A bonus test case from [scala-user]

Thanks to Ilya Denisov for another sample [1] that progressed
with the fix for SI-7239, 174334b.

  [1] https://groups.google.com/forum/#!topic/scala-user/8rZeCeiTYDo
Merge pull request #3032 from retronym/ticket/7239-test

SI-7239 A bonus test case from [scala-user]