scala/scala — pull request #3416 by retronym (2014-01-27 09:48:27+00:00)
Title: Prohibit views targeting AnyVal

Library changes in Scala 2.10 mean that we are left with the
unfortunate situation of admitting:

scala> "": AnyVal
res0: AnyVal =

We already have explicit checks in place to prevent views
targeting `AnyRef`. This commit balances this out by prohibiting
`AnyVal`, as well.

The enclosed test shows that this case is now prevented. If multiple
implicits views are applicable, the ambiguity error is still raised;
these check comes right at the end. Maybe that ought to be changed,
but I don't think it matters too much.

I've also disabled this prohibition under -Xsource:2.10.

Review by @adriaanm