Merge branch 'merge-2.10.wip-x' into merge-2.10.x-master

* merge-2.10.wip-x: (24 commits)
  SI-6023 reify abstract vals
  Removing controversial `either` method from Futures API.
  SI-6695 Test case for fixed Array match bug
  adds comments to standard attachments
  SI-6673 fixes macro problems with eta expansions
  Restore the opimization apparently lost after merge.
  SI-6624 set info of case pattern binder to help find case field accessors
  Scaladoc update for collection.mutable.MultiMap
  SI-6663: don't ignore type parameter on selectDynamic invocation
  SI-6551: don't insert apply call in polymorphic expression.
  SI-6634 Fixes data corruption issue in ListBuffer#remove
  Fixes SI-6628, Revert "Fix for view isEmpty."
  SI-6661 - Remove obsolete implicit parameter of scala.concurrent.promise method
  Fixes SI-6150 - backport to 2.10.x branch.
  SI-5330, SI-6014 deal with existential self-type
  Fixes SI-6559 - StringContext not using passed in escape function.
  SI-6648 copyAttrs must preserve TypeTree#wasEmpty
  Fix raw string interpolator: string parts which were after the first argument were still escaped
  sane printing of renamed imports
  SI-6440 Address regressions around MissingRequirementError
  ...

Conflicts:
	src/library/scala/collection/generic/IndexedSeqFactory.scala
	src/library/scala/collection/mutable/ListBuffer.scala
	src/reflect/scala/reflect/internal/Symbols.scala
	src/reflect/scala/reflect/internal/Types.scala
	test/files/run/t6150.scala

1 files changed, 7 insertions, 2 deletions

diff --git a/src/reflect/scala/reflect/internal/pickling/UnPickler.scala b/src/reflect/scala/reflect/internal/pickling/UnPickler.scala
index 2dab9b37b4..5a0454a569 100644
--- a/src/reflect/scala/reflect/internal/pickling/UnPickler.scala
+++ b/src/reflect/scala/reflect/internal/pickling/UnPickler.scala
@@ -20,7 +20,7 @@ import scala.annotation.switch
 /** @author Martin Odersky
  *  @version 1.0
  */
-abstract class UnPickler /*extends scala.reflect.generic.UnPickler*/ {
+abstract class UnPickler {
   val global: SymbolTable
   import global._
 
@@ -232,7 +232,12 @@ abstract class UnPickler /*extends scala.reflect.generic.UnPickler*/ {
               // (4) Call the mirror's "missing" hook.
               adjust(mirrorThatLoaded(owner).missingHook(owner, name)) orElse {
                 // (5) Create a stub symbol to defer hard failure a little longer.
-                owner.newStubSymbol(name)
+                val missingMessage =
+                  s"""|bad symbolic reference. A signature in $filename refers to ${name.longString}
+                      |in ${owner.kindString} ${owner.fullName} which is not available.
+                      |It may be completely missing from the current classpath, or the version on
+                      |the classpath might be incompatible with the version used when compiling $filename.""".stripMargin
+                owner.newStubSymbol(name, missingMessage)
               }
             }
           }