scala/scala — pull request #458 by adriaanm (2012-05-02 10:42:26+00:00)
Title: SI-5729: TypeVar experimentals iff -Xexperimental

it used to also be enabled by -Yvirtpatmat, which is now on by default,
but this type hackery is no longer necessary to bootstrap under the new pattern matching scheme,
so let's only turn it on when people are feeling -Xexperimental