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, 19 insertions, 14 deletions

diff --git a/src/reflect/scala/reflect/internal/Symbols.scala b/src/reflect/scala/reflect/internal/Symbols.scala
index 032c75f6df..ad7dbe5ef1 100644
--- a/src/reflect/scala/reflect/internal/Symbols.scala
+++ b/src/reflect/scala/reflect/internal/Symbols.scala
@@ -404,9 +404,9 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
      *  failure to the point when that name is used for something, which is
      *  often to the point of never.
      */
-    def newStubSymbol(name: Name): Symbol = name match {
-      case n: TypeName  => new StubClassSymbol(this, n)
-      case _            => new StubTermSymbol(this, name.toTermName)
+    def newStubSymbol(name: Name, missingMessage: String): Symbol = name match {
+      case n: TypeName  => new StubClassSymbol(this, n, missingMessage)
+      case _            => new StubTermSymbol(this, name.toTermName, missingMessage)
     }
 
     @deprecated("Use the other signature", "2.10.0")
@@ -1360,6 +1360,9 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
       }
     }
 
+    /** Raises a `MissingRequirementError` if this symbol is a `StubSymbol` */
+    def failIfStub() {}
+
     /** Initialize the symbol */
     final def initialize: this.type = {
       if (!isInitialized) info
@@ -3066,14 +3069,20 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
     )
   }
   trait StubSymbol extends Symbol {
-    protected def stubWarning = {
-      val from = if (associatedFile == null) "" else s" - referenced from ${associatedFile.canonicalPath}"
-      s"$kindString $nameString$locationString$from (a classfile may be missing)"
-    }
+    devWarning("creating stub symbol to defer error: " + missingMessage)
+
+    protected def missingMessage: String
+
+    /** Fail the stub by throwing a [[scala.reflect.internal.MissingRequirementError]]. */
+    override final def failIfStub() = {MissingRequirementError.signal(missingMessage)} //
+
+    /** Fail the stub by reporting an error to the reporter, setting the IS_ERROR flag
+      * on this symbol, and returning the dummy value `alt`.
+      */
     private def fail[T](alt: T): T = {
       // Avoid issuing lots of redundant errors
       if (!hasFlag(IS_ERROR)) {
-        globalError(s"bad symbolic reference to " + stubWarning)
+        globalError(missingMessage)
         if (settings.debug.value)
           (new Throwable).printStackTrace
 
@@ -3089,13 +3098,9 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
     override def info            = fail(NoType)
     override def rawInfo         = fail(NoType)
     override def companionSymbol = fail(NoSymbol)
-
-    locally {
-      devWarning("creating stub symbol for " + stubWarning)
-    }
   }
-  class StubClassSymbol(owner0: Symbol, name0: TypeName) extends ClassSymbol(owner0, owner0.pos, name0) with StubSymbol
-  class StubTermSymbol(owner0: Symbol, name0: TermName) extends TermSymbol(owner0, owner0.pos, name0) with StubSymbol
+  class StubClassSymbol(owner0: Symbol, name0: TypeName, protected val missingMessage: String) extends ClassSymbol(owner0, owner0.pos, name0) with StubSymbol
+  class StubTermSymbol(owner0: Symbol, name0: TermName, protected val missingMessage: String) extends TermSymbol(owner0, owner0.pos, name0) with StubSymbol
 
   trait FreeSymbol extends Symbol {
     def origin: String