Following up on things that -Xlint told me, som...

Following up on things that -Xlint told me, sometimes because Mr. Linty
was being sensible and other times just to shut him up so we can hear
better in the future.

- made xml.Equality public because it occurs in public method signatures
- made some actor classes with inaccessible-unoverridable methods final
- eliminated a bunch of "dead code follows" warnings by deleting the
dead code which really did follow - improved the reliability of warnings
about inaccessible types

For the changes in actors, review by phaller.

19 files changed, 52 insertions, 41 deletions

diff --git a/src/compiler/scala/reflect/internal/Definitions.scala b/src/compiler/scala/reflect/internal/Definitions.scala
index d076e80836..32e0b35d18 100644
--- a/src/compiler/scala/reflect/internal/Definitions.scala
+++ b/src/compiler/scala/reflect/internal/Definitions.scala
@@ -255,14 +255,16 @@ trait Definitions extends reflect.api.StandardDefinitions {
 
     // classes with special meanings
     lazy val StringAddClass   = getClass("scala.runtime.StringAdd")
+    lazy val ArrowAssocClass  = getClass("scala.Predef.ArrowAssoc")
     lazy val StringAdd_+      = getMember(StringAddClass, nme.PLUS)
     lazy val NotNullClass     = getClass("scala.NotNull")
     lazy val DelayedInitClass = getClass("scala.DelayedInit")
       def delayedInitMethod = getMember(DelayedInitClass, nme.delayedInit)
       // a dummy value that communicates that a delayedInit call is compiler-generated
       // from phase UnCurry to phase Constructors
-      def delayedInitArgVal = EmptyPackageClass.newValue(NoPosition, nme.delayedInitArg)
-        .setInfo(UnitClass.tpe)
+      // !!! This is not used anywhere (it was checked in that way.)
+      // def delayedInitArgVal = EmptyPackageClass.newValue(NoPosition, nme.delayedInitArg)
+      //   .setInfo(UnitClass.tpe)
 
     lazy val TypeConstraintClass   = getClass("scala.annotation.TypeConstraint")
     lazy val SingletonClass        = newClass(ScalaPackageClass, tpnme.Singleton, anyparam) setFlag (ABSTRACT | TRAIT | FINAL)
@@ -371,6 +373,7 @@ trait Definitions extends reflect.api.StandardDefinitions {
 
     // The given symbol represents either String.+ or StringAdd.+
     def isStringAddition(sym: Symbol) = sym == String_+ || sym == StringAdd_+
+    def isArrowAssoc(sym: Symbol) = ArrowAssocClass.tpe.decls.toList contains sym
 
     def isOptionType(tp: Type)  = cond(tp.normalize) { case TypeRef(_, OptionClass, List(_)) => true }
     def isSomeType(tp: Type)    = cond(tp.normalize) { case TypeRef(_,   SomeClass, List(_)) => true }
@@ -450,7 +453,7 @@ trait Definitions extends reflect.api.StandardDefinitions {
         }
       }
 
-    /** if tpe <: ProductN[T1,...,TN], returns Some(T1,...,TN) else None */
+    /** if tpe <: ProductN[T1,...,TN], returns Some((T1,...,TN)) else None */
     def getProductArgs(tpe: Type): Option[List[Type]] =
       tpe.baseClasses collectFirst { case x if isExactProductType(x.tpe) => tpe.baseType(x).typeArgs }
 
diff --git a/src/compiler/scala/reflect/internal/TreeInfo.scala b/src/compiler/scala/reflect/internal/TreeInfo.scala
index afb56d9999..a8ec7e34f5 100644
--- a/src/compiler/scala/reflect/internal/TreeInfo.scala
+++ b/src/compiler/scala/reflect/internal/TreeInfo.scala
@@ -410,7 +410,7 @@ abstract class TreeInfo {
   }
   object IsIf extends SeeThroughBlocks[Option[(Tree, Tree, Tree)]] {
     protected def unapplyImpl(x: Tree) = x match {
-      case If(cond, thenp, elsep) => Some(cond, thenp, elsep)
+      case If(cond, thenp, elsep) => Some((cond, thenp, elsep))
       case _                      => None
     }
   }
diff --git a/src/compiler/scala/reflect/internal/Types.scala b/src/compiler/scala/reflect/internal/Types.scala
index c34d285d9e..545b86f6ab 100644
--- a/src/compiler/scala/reflect/internal/Types.scala
+++ b/src/compiler/scala/reflect/internal/Types.scala
@@ -116,7 +116,7 @@ trait Types extends api.Types { self: SymbolTable =>
     }
 
     private[Types] def record(tv: TypeVar) = {
-      log ::= (tv, tv.constr.cloneInternal)
+      log ::= ((tv, tv.constr.cloneInternal))
     }
     private[scala] def clear() {
       if (settings.debug.value)
diff --git a/src/compiler/scala/reflect/internal/transform/Erasure.scala b/src/compiler/scala/reflect/internal/transform/Erasure.scala
index dec20a130e..6896a4aa5f 100644
--- a/src/compiler/scala/reflect/internal/transform/Erasure.scala
+++ b/src/compiler/scala/reflect/internal/transform/Erasure.scala
@@ -24,7 +24,7 @@ trait Erasure {
     }
 
     /** If `tp` is of the form Array[...Array[T]...] where `T` is an abstract type
-     *  then Some(N, T) where N is the number of Array constructors enclosing `T`,
+     *  then Some((N, T)) where N is the number of Array constructors enclosing `T`,
      *  otherwise None. Existentials on any level are ignored.
      */
     def unapply(tp: Type): Option[(Int, Type)] = tp.normalize match {
@@ -36,7 +36,7 @@ trait Erasure {
               case None => None
             }
           case core =>
-            Some(1, core)
+            Some((1, core))
         }
       case ExistentialType(tparams, restp) =>
         unapply(restp)
diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index cf2814165a..ac9f853477 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -185,7 +185,7 @@ self =>
 
     override def blockExpr(): Tree = skipBraces(EmptyTree)
 
-    override def templateBody(isPre: Boolean) = skipBraces(emptyValDef, List(EmptyTree))
+    override def templateBody(isPre: Boolean) = skipBraces((emptyValDef, List(EmptyTree)))
   }
 
   class UnitParser(val unit: global.CompilationUnit, patches: List[BracePatch]) extends SourceFileParser(unit.source) {
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
index 03de24c550..70dd8cd920 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
@@ -1106,7 +1106,7 @@ abstract class GenJVM extends SubComponent with GenJVMUtil with GenAndroid with
           if (! (covered contains b) ) {
             if (start >= 0) { // we're inside a handler range
               end = labels(b).getAnchor()
-              ranges ::= (start, end)
+              ranges ::= ((start, end))
               start = -1
             }
           } else {
@@ -1123,7 +1123,7 @@ abstract class GenJVM extends SubComponent with GenJVMUtil with GenAndroid with
          * code!
          */
         if (start >= 0) {
-          ranges ::= (start, jcode.getPC())
+          ranges ::= ((start, jcode.getPC()))
         }
 
         if (!covered.isEmpty)
diff --git a/src/compiler/scala/tools/nsc/interactive/Global.scala b/src/compiler/scala/tools/nsc/interactive/Global.scala
index a093c875b8..fc53a34c45 100644
--- a/src/compiler/scala/tools/nsc/interactive/Global.scala
+++ b/src/compiler/scala/tools/nsc/interactive/Global.scala
@@ -589,7 +589,7 @@ class Global(settings: Settings, reporter: Reporter, projectName: String = "")
     }
     sources foreach (removeUnitOf(_))
     minRunId = currentRunId
-    respond(response) ()
+    respond(response)(())
     demandNewCompilerRun()
   }
 
diff --git a/src/compiler/scala/tools/nsc/matching/Patterns.scala b/src/compiler/scala/tools/nsc/matching/Patterns.scala
index b25bf2d649..3abb0c5ba3 100644
--- a/src/compiler/scala/tools/nsc/matching/Patterns.scala
+++ b/src/compiler/scala/tools/nsc/matching/Patterns.scala
@@ -316,7 +316,7 @@ trait Patterns extends ast.TreeDSL {
         case UnApply(
         Apply(TypeApply(Select(qual, nme.unapplySeq), List(tpt)), _),
         List(ArrayValue(_, elems))) =>
-          Some(qual.symbol, tpt, elems)
+          Some((qual.symbol, tpt, elems))
         case _ =>
           None
        }
diff --git a/src/compiler/scala/tools/nsc/settings/FscSettings.scala b/src/compiler/scala/tools/nsc/settings/FscSettings.scala
index bb62750026..bb6e2ad920 100644
--- a/src/compiler/scala/tools/nsc/settings/FscSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/FscSettings.scala
@@ -24,7 +24,7 @@ class FscSettings(error: String => Unit) extends Settings(error) {
   val server       = StringSetting ("-server",   "hostname:portnumber", "Specify compile server socket", "")
   val preferIPv4   = BooleanSetting("-ipv4",     "Use IPv4 rather than IPv6 for the server socket")
   val idleMins     = IntSetting    ("-max-idle", "Set idle timeout in minutes for fsc (use 0 for no timeout)",
-                                              30, Some(0, Int.MaxValue), (_: String) => None)
+                                              30, Some((0, Int.MaxValue)), (_: String) => None)
 
   // For improved help output, separating fsc options from the others.
   def fscSpecific = Set[Settings#Setting](
diff --git a/src/compiler/scala/tools/nsc/settings/MutableSettings.scala b/src/compiler/scala/tools/nsc/settings/MutableSettings.scala
index b96d9fbb1e..96175ff89d 100644
--- a/src/compiler/scala/tools/nsc/settings/MutableSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/MutableSettings.scala
@@ -263,7 +263,7 @@ class MutableSettings(val errorFn: String => Unit)
 
     def add(src: AbstractFile, dst: AbstractFile) {
       singleOutDir = None
-      outputDirs ::= (src, dst)
+      outputDirs ::= ((src, dst))
     }
 
     /** Return the list of source-destination directory pairs. */
diff --git a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
index 6325fd6eb4..ed432562dc 100644
--- a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
@@ -59,7 +59,7 @@ trait ScalaSettings extends AbsScalaSettings
   val future        = BooleanSetting    ("-Xfuture", "Turn on future language features.")
   val genPhaseGraph = StringSetting     ("-Xgenerate-phase-graph", "file", "Generate the phase graphs (outputs .dot files) to fileX.dot.", "")
   val XlogImplicits = BooleanSetting    ("-Xlog-implicits", "Show more detail on why some implicits are not applicable.")
-  val maxClassfileName = IntSetting     ("-Xmax-classfile-name", "Maximum filename length for generated classes", 255, Some(72, 255), _ => None)
+  val maxClassfileName = IntSetting     ("-Xmax-classfile-name", "Maximum filename length for generated classes", 255, Some((72, 255)), _ => None)
   val Xmigration28  = BooleanSetting    ("-Xmigration", "Warn about constructs whose behavior may have changed between 2.7 and 2.8.")
   val nouescape     = BooleanSetting    ("-Xno-uescape", "Disable handling of \\u unicode escapes.")
   val Xnojline      = BooleanSetting    ("-Xnojline", "Do not use JLine for editing.")
@@ -121,7 +121,7 @@ trait ScalaSettings extends AbsScalaSettings
   val Yprofile      = PhasesSetting     ("-Yprofile", "(Requires jvm -agentpath to contain yjgpagent) Profile CPU usage of given phases.")
   val YprofileMem   = BooleanSetting    ("-Yprofile-memory", "Profile memory, get heap snapshot after each compiler run (requires yjpagent, see above).")
   val YprofileClass = StringSetting     ("-Yprofile-class", "class", "Name of profiler class.", "scala.tools.util.YourkitProfiling")
-  val Yrecursion    = IntSetting        ("-Yrecursion", "Set recursion depth used when locking symbols.", 0, Some(0, Int.MaxValue), (_: String) => None)
+  val Yrecursion    = IntSetting        ("-Yrecursion", "Set recursion depth used when locking symbols.", 0, Some((0, Int.MaxValue)), (_: String) => None)
   val selfInAnnots  = BooleanSetting    ("-Yself-in-annots", "Include a \"self\" identifier inside of annotations.")
   val Xshowtrees    = BooleanSetting    ("-Yshow-trees", "(Requires -Xprint:) Print detailed ASTs.")
   val Yshowsyms     = BooleanSetting    ("-Yshow-syms", "Print the AST symbol hierarchy after each phase.")
@@ -170,7 +170,7 @@ trait ScalaSettings extends AbsScalaSettings
 
   val YpresentationLog     = StringSetting("-Ypresentation-log", "file", "Log presentation compiler events into file", "")
   val YpresentationReplay  = StringSetting("-Ypresentation-replay", "file", "Replay presentation compiler events from file", "")
-  val YpresentationDelay   = IntSetting("-Ypresentation-delay", "Wait number of ms after typing before starting typechecking", 0, Some(0, 999), str => Some(str.toInt))
+  val YpresentationDelay   = IntSetting("-Ypresentation-delay", "Wait number of ms after typing before starting typechecking", 0, Some((0, 999)), str => Some(str.toInt))
 
   /**
    * -P "Plugin" settings
diff --git a/src/compiler/scala/tools/nsc/transform/Constructors.scala b/src/compiler/scala/tools/nsc/transform/Constructors.scala
index e0c6e8678b..b5b770b003 100644
--- a/src/compiler/scala/tools/nsc/transform/Constructors.scala
+++ b/src/compiler/scala/tools/nsc/transform/Constructors.scala
@@ -230,7 +230,7 @@ abstract class Constructors extends Transform with ast.TreeDSL {
             case DefDef(_, _, _, _, _, body)
             if (tree.symbol.isOuterAccessor && tree.symbol.owner == clazz && clazz.isFinal) =>
               log("outerAccessors += " + tree.symbol.fullName)
-              outerAccessors ::= (tree.symbol, body)
+              outerAccessors ::= ((tree.symbol, body))
             case Select(_, _) =>
               if (!mustbeKept(tree.symbol)) {
                 log("accessedSyms += " + tree.symbol.fullName)
diff --git a/src/compiler/scala/tools/nsc/typechecker/Adaptations.scala b/src/compiler/scala/tools/nsc/typechecker/Adaptations.scala
index 3dee4650de..99d5363d5e 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Adaptations.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Adaptations.scala
@@ -59,6 +59,7 @@ trait Adaptations {
         // an opt-in compiler option is given.
         oneArgObject && !(
              isStringAddition(t.symbol)
+          || isArrowAssoc(t.symbol)
           || t.symbol.name == nme.equals_
           || t.symbol.name == nme.EQ
           || t.symbol.name == nme.NE
diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
index 765881ac81..097bbf5915 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
@@ -219,7 +219,7 @@ trait Implicits {
   object Function1 {
     val Sym = FunctionClass(1)
     def unapply(tp: Type) = tp match {
-      case TypeRef(_, Sym, arg1 :: arg2 :: _) => Some(arg1, arg2)
+      case TypeRef(_, Sym, arg1 :: arg2 :: _) => Some((arg1, arg2))
       case _                                  => None
     }
   }
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 8e1ee97387..37b5870ac5 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -1221,22 +1221,27 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R
           otherSym.decodedName, cannot, memberSym.decodedName)
       )
     }
+
     /** Warn about situations where a method signature will include a type which
      *  has more restrictive access than the method itself.
      */
     private def checkAccessibilityOfReferencedTypes(tree: Tree) {
       val member = tree.symbol
 
-      // types of the value parameters
-      member.paramss.flatten foreach { p =>
-        val normalized = p.tpe.normalize
-        if ((normalized ne p.tpe) && lessAccessibleSymsInType(normalized, member).isEmpty) ()
-        else lessAccessibleSymsInType(p.tpe, member) foreach (sym => warnLessAccessible(sym, member))
+      def checkAccessibilityOfType(tpe: Type) {
+        val inaccessible = lessAccessibleSymsInType(tpe, member)
+        // if the unnormalized type is accessible, that's good enough
+        if (inaccessible.isEmpty) ()
+        // or if the normalized type is, that's good too
+        else if ((tpe ne tpe.normalize) && lessAccessibleSymsInType(tpe.normalize, member).isEmpty) ()
+        // otherwise warn about the inaccessible syms in the unnormalized type
+        else inaccessible foreach (sym => warnLessAccessible(sym, member))
       }
+
+      // types of the value parameters
+      member.paramss.flatten foreach (p => checkAccessibilityOfType(p.tpe))
       // upper bounds of type parameters
-      member.typeParams.map(_.info.bounds.hi.widen) foreach { tp =>
-        lessAccessibleSymsInType(tp, member) foreach (sym => warnLessAccessible(sym, member))
-      }
+      member.typeParams.map(_.info.bounds.hi.widen) foreach checkAccessibilityOfType
     }
 
     /** Check that a deprecated val or def does not override a
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 4125ab0285..23482eb609 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -2118,6 +2118,8 @@ trait Typers extends Modes with Adaptations {
               } else {
                 val localTyper = if (inBlock || (stat.isDef && !stat.isInstanceOf[LabelDef])) this
                                  else newTyper(context.make(stat, exprOwner))
+                // XXX this creates a spurious dead code warning if an exception is thrown
+                // in a constructor, even if it is the only thing in the constructor.
                 val result = checkDead(localTyper.typed(stat, EXPRmode | BYVALmode, WildcardType))
                 if (treeInfo.isSelfOrSuperConstrCall(result)) {
                   context.inConstructorSuffix = true
@@ -2202,7 +2204,7 @@ trait Typers extends Modes with Adaptations {
           }) ::: newStats.toList
         }
       }
-      val result = stats mapConserve (typedStat)
+      val result = stats mapConserve typedStat
       if (phase.erasedTypes) result
       else checkNoDoubleDefsAndAddSynthetics(result)
     }
diff --git a/src/compiler/scala/tools/reflect/Invoked.scala b/src/compiler/scala/tools/reflect/Invoked.scala
index fbc528ea45..30c6201a0d 100644
--- a/src/compiler/scala/tools/reflect/Invoked.scala
+++ b/src/compiler/scala/tools/reflect/Invoked.scala
@@ -34,18 +34,18 @@ object Invoked {
     new Invoked(proxy, m, fixedArgs)
   }
   def unapply(x: Any) = x match {
-    case x: Invoked => Some(x.proxy, x.m, x.args)
+    case x: Invoked => Some((x.proxy, x.m, x.args))
     case _          => None
   }
   object NameAndArgs {
     def unapply(x: Any) = x match {
-      case x: Invoked => Some(x.name, x.args)
+      case x: Invoked => Some((x.name, x.args))
       case _          => None
     }
   }
   object NameAndArity {
     def unapply(x: Any) = x match {
-      case x: Invoked => Some(x.name, x.arity)
+      case x: Invoked => Some((x.name, x.arity))
       case _          => None
     }
   }
diff --git a/src/compiler/scala/tools/util/Javap.scala b/src/compiler/scala/tools/util/Javap.scala
index 679fc0965b..04033e913d 100644
--- a/src/compiler/scala/tools/util/Javap.scala
+++ b/src/compiler/scala/tools/util/Javap.scala
@@ -121,15 +121,15 @@ object Javap {
     }
     private val envActionMap: Map[String, (String, Any)] = {
       val map = Map(
-        "-l"         -> ("showLineAndLocal", true),
-        "-c"         -> ("showDisassembled", true),
-        "-s"         -> ("showInternalSigs", true),
-        "-verbose"   -> ("showVerbose", true),
-        "-private"   -> ("showAccess", Access.PRIVATE),
-        "-package"   -> ("showAccess", Access.PACKAGE),
-        "-protected" -> ("showAccess", Access.PROTECTED),
-        "-public"    -> ("showAccess", Access.PUBLIC),
-        "-all"       -> ("showallAttr", true)
+        "-l"         -> (("showLineAndLocal", true)),
+        "-c"         -> (("showDisassembled", true)),
+        "-s"         -> (("showInternalSigs", true)),
+        "-verbose"   -> (("showVerbose", true)),
+        "-private"   -> (("showAccess", Access.PRIVATE)),
+        "-package"   -> (("showAccess", Access.PACKAGE)),
+        "-protected" -> (("showAccess", Access.PROTECTED)),
+        "-public"    -> (("showAccess", Access.PUBLIC)),
+        "-all"       -> (("showallAttr", true))
       )
       map ++ List(
         "-v" -> map("-verbose"),
diff --git a/src/compiler/scala/tools/util/StringOps.scala b/src/compiler/scala/tools/util/StringOps.scala
index 65ff582011..2773aad87f 100644
--- a/src/compiler/scala/tools/util/StringOps.scala
+++ b/src/compiler/scala/tools/util/StringOps.scala
@@ -52,7 +52,7 @@ trait StringOps {
 
   def splitAt(str: String, idx: Int, doDropIndex: Boolean = false): Option[(String, String)] =
     if (idx == -1) None
-    else Some(str take idx, str drop (if (doDropIndex) idx + 1 else idx))
+    else Some((str take idx, str drop (if (doDropIndex) idx + 1 else idx)))
 
   /** Returns a string meaning "n elements".
    *