scala/scala — pull request #2637 by retronym (2013-06-06 13:01:03+00:00)
Title: SI-7439 Avoid NPE in `isMonomorphicType` with stub symbols. …

`originalInfo` can return null for stub symbols; deal with that
as we used to before a regression in 016bc3d.

After this change, we can once again delete A_1.class and still compile
code instantiating B_1. (A_1 is only referred to in a method signature
of B_1 which is not called from our code.)

scala> new B_1
warning: Class A_1 not found - continuing with a stub.
res0: B_1 = B_1@5284b8f

In practice, this situation arises when someone uses a third
party class that was compiled against other libraries not avaialable
on the current compilation classpath.

Review by @paulp