Warnings not shown in the REPL

[smarter]

The same code compiled by hand does show the warning:

scala> def foo(x: Option[Int]) = x match { case None => }
def foo(x: Option[Int]): Unit
scala>

Could you have a look @liufengyun ?

[allanrenucci]

This is a known issue (at least to me 😄). Warnings are not reported in the REPL.