scala/scala — pull request #3204 by retronym (2013-11-29 10:21:25+00:00)
Title: Test case for recently improved unchecked warning

Prior to https://github.com/scala/scala/pull/2848, the enclosed
test compiled without warning and printed:

true
false

Features interacting:
- implicit class tags to enable type patterns on abstract types
- type tests on compound types.

I think the unchecked warning is acceptable for now.