scala/scala — pull request #743 by axel22 (2012-06-18 17:37:22+00:00)
Title: Fix SI-4541.

Catch type errors when duplicating trees.
In this case, to access a protected member from a specialized
class is an error, so we would have to make the member public
anyway.
Better it is then to report an error and have the user make the
field public explicitly.

Review by @dragos.