The real warning is issued in the correct spot just above. I'm not sure why we used to warn at this location (sym.pos).

Interestingly, this warning recently was eliminated on master, too, but through different means:

```
% git show c58b7b10249adefa1045942a1dc7a55dc5932db8 -- test/files/neg/classmanifests_new_deprecations.check
commit c58b7b10249adefa1045942a1dc7a55dc5932db8
Author: Paul Phillips <paulp@improving.org>
Date:   Wed Sep 4 08:22:27 2013 -0700

    Eliminate TypeTrees with null original.

    This is a retry of #2801 after figuring out the range position
    error. Should there be anyone out there who compiles with -Xdev,
    know that this commit eliminates the 1406 errors one presently
    incurs compiling src/library.

    A val declared in source code receives only one tree from the
    parser, but two are needed - one for the field and one for the
    getter. I discovered long ago that if the val had an existential
    type, this was creating issues with incompatible existentials
    between the field and the getter. However the remedy for that
    did not take into account the whole of the wide range of super
    subtle issues which accompany tree duplication.

    In particular, the duplicated tree must be given not only a
    fresh TypeTree(), but that TypeTree cannot share the same
    original without running afoul of range position invariants.
    That's because typedTypeTree resurrects the original tree with
    whatever position it has - so the "original" needs to be a
    duplicate of the original with a focused position.

    Should the call to TypeTree.duplicate also duplicate the original?
    I think so, but I bequeath this question to others.

    This commit also eliminated some duplicate error messages, because
    duplicate suppression depends on the errors having the same position.

    See c478eb770d, 7a6fa80937 for previous related work.

diff --git a/test/files/neg/classmanifests_new_deprecations.check b/test/files/neg/c
index 5f9d0a1..fd1e272 100644
--- a/test/files/neg/classmanifests_new_deprecations.check
+++ b/test/files/neg/classmanifests_new_deprecations.check
@@ -7,9 +7,6 @@ classmanifests_new_deprecations.scala:3: warning: type ClassManifest
 classmanifests_new_deprecations.scala:4: warning: type ClassManifest in object Pred
   val cm3: ClassManifest[Int] = null
            ^
-classmanifests_new_deprecations.scala:4: warning: type ClassManifest in object Pred
-  val cm3: ClassManifest[Int] = null
-      ^
 classmanifests_new_deprecations.scala:6: warning: type ClassManifest in package ref
   def rcm1[T: scala.reflect.ClassManifest] = ???
             ^
@@ -19,9 +16,6 @@ classmanifests_new_deprecations.scala:7: warning: type ClassManife
 classmanifests_new_deprecations.scala:8: warning: type ClassManifest in package ref
   val rcm3: scala.reflect.ClassManifest[Int] = null
                           ^
-classmanifests_new_deprecations.scala:8: warning: type ClassManifest in package ref
-  val rcm3: scala.reflect.ClassManifest[Int] = null
-      ^
 classmanifests_new_deprecations.scala:10: warning: type ClassManifest in object Pre
   type CM[T] = ClassManifest[T]
                ^
@@ -29,5 +23,5 @@ classmanifests_new_deprecations.scala:15: warning: type ClassManif
   type RCM[T] = scala.reflect.ClassManifest[T]
                               ^
 error: No warnings can be incurred under -Xfatal-warnings.
-10 warnings found
+8 warnings found
 one error found
```