Merge pull request #2343 from retronym/topic/merge-2.10.x-to-v2.11.0-M2-74-g00e6c8b

Merge 2.10.x to master

15 files changed, 144 insertions, 92 deletions

diff --git a/src/compiler/scala/reflect/reify/utils/Extractors.scala b/src/compiler/scala/reflect/reify/utils/Extractors.scala
index d57188bf6e..7338df1f72 100644
--- a/src/compiler/scala/reflect/reify/utils/Extractors.scala
+++ b/src/compiler/scala/reflect/reify/utils/Extractors.scala
@@ -164,51 +164,30 @@ trait Extractors {
     }
   }
 
-  object FreeDef {
-    def unapply(tree: Tree): Option[(Tree, TermName, Tree, Long, String)] = tree match {
-      case FreeTermDef(uref, name, binding, flags, origin) =>
-        Some((uref, name, binding, flags, origin))
-      case FreeTypeDef(uref, name, binding, flags, origin) =>
-        Some((uref, name, binding, flags, origin))
-      case _ =>
-        None
-    }
-  }
-
-  object FreeTermDef {
-    def unapply(tree: Tree): Option[(Tree, TermName, Tree, Long, String)] = tree match {
-      case
-        ValDef(_, name, _, Apply(
-          Select(Select(uref1 @ Ident(_), build1), newFreeTerm),
-          List(
-            _,
-            _,
-            Apply(Select(Select(uref2 @ Ident(_), build2), flagsFromBits), List(Literal(Constant(flags: Long)))),
-            Literal(Constant(origin: String)))))
-      if uref1.name == nme.UNIVERSE_SHORT && build1 == nme.build && newFreeTerm == nme.newFreeTerm &&
-         uref2.name == nme.UNIVERSE_SHORT && build2 == nme.build && flagsFromBits == nme.flagsFromBits =>
-        Some((uref1, name, reifyBinding(tree), flags, origin))
-      case _ =>
-        None
-    }
-  }
-
-  object FreeTypeDef {
-    def unapply(tree: Tree): Option[(Tree, TermName, Tree, Long, String)] = tree match {
-      case
-        ValDef(_, name, _, Apply(
-          Select(Select(uref1 @ Ident(_), build1), newFreeType),
-          List(
-            _,
-            Apply(Select(Select(uref2 @ Ident(_), build2), flagsFromBits), List(Literal(Constant(flags: Long)))),
-            Literal(Constant(origin: String)))))
-      if uref1.name == nme.UNIVERSE_SHORT && build1 == nme.build && newFreeType == nme.newFreeType &&
-         uref2.name == nme.UNIVERSE_SHORT && build2 == nme.build && flagsFromBits == nme.flagsFromBits =>
-        Some((uref1, name, reifyBinding(tree), flags, origin))
-      case _ =>
-        None
+  sealed abstract class FreeDefExtractor(acceptTerms: Boolean, acceptTypes: Boolean) {
+    def unapply(tree: Tree): Option[(Tree, TermName, Tree, Long, String)] = {
+      def acceptFreeTermFactory(name: Name) = {
+        (acceptTerms && name == nme.newFreeTerm) ||
+        (acceptTypes && name == nme.newFreeType)
+      }
+      tree match {
+        case
+          ValDef(_, name, _, Apply(
+            Select(Select(uref1 @ Ident(_), build1), freeTermFactory),
+            _ :+
+            Apply(Select(Select(uref2 @ Ident(_), build2), flagsFromBits), List(Literal(Constant(flags: Long)))) :+
+            Literal(Constant(origin: String))))
+        if uref1.name == nme.UNIVERSE_SHORT && build1 == nme.build && acceptFreeTermFactory(freeTermFactory) &&
+           uref2.name == nme.UNIVERSE_SHORT && build2 == nme.build && flagsFromBits == nme.flagsFromBits =>
+          Some((uref1, name, reifyBinding(tree), flags, origin))
+        case _ =>
+          None
+      }
     }
   }
+  object FreeDef extends FreeDefExtractor(acceptTerms = true, acceptTypes = true)
+  object FreeTermDef extends FreeDefExtractor(acceptTerms = true, acceptTypes = false)
+  object FreeTypeDef extends FreeDefExtractor(acceptTerms = false, acceptTypes = true)
 
   object FreeRef {
     def unapply(tree: Tree): Option[(Tree, TermName)] = tree match {
diff --git a/src/compiler/scala/tools/nsc/backend/icode/Members.scala b/src/compiler/scala/tools/nsc/backend/icode/Members.scala
index e471f4256b..0a18adcf4f 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/Members.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/Members.scala
@@ -172,6 +172,7 @@ trait Members {
     var returnType: TypeKind = _
     var recursive: Boolean = false
     var bytecodeHasEHs = false // set by ICodeReader only, used by Inliner to prevent inlining (SI-6188)
+    var bytecodeHasInvokeDynamic = false // set by ICodeReader only, used by Inliner to prevent inlining until we have proper invoke dynamic support
 
     /** local variables and method parameters */
     var locals: List[Local] = Nil
diff --git a/src/compiler/scala/tools/nsc/backend/icode/Opcodes.scala b/src/compiler/scala/tools/nsc/backend/icode/Opcodes.scala
index d8aac8e9db..ff118be3c4 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/Opcodes.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/Opcodes.scala
@@ -394,6 +394,25 @@ trait Opcodes { self: ICodes =>
 
       override def category = mthdsCat
     }
+    
+    /**
+     * A place holder entry that allows us to parse class files with invoke dynamic
+     * instructions. Because the compiler doesn't yet really understand the
+     * behavior of invokeDynamic, this op acts as a poison pill. Any attempt to analyze
+     * this instruction will cause a failure. The only optimization that
+     * should ever look at non-Scala generated icode is the inliner, and it
+     * has been modified to not examine any method with invokeDynamic 
+     * instructions. So if this poison pill ever causes problems then
+     * there's been a serious misunderstanding
+     */
+    // TODO do the real thing
+    case class INVOKE_DYNAMIC(poolEntry: Char) extends Instruction {
+      private def error = sys.error("INVOKE_DYNAMIC is not fully implemented and should not be analyzed")
+      override def consumed = error
+      override def produced = error
+      override def producedTypes = error
+      override def category = error
+    }
 
     case class BOX(boxType: TypeKind) extends Instruction {
       assert(boxType.isValueType && (boxType ne UNIT)) // documentation
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
index 78fb109b42..0c098edf98 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
@@ -2251,16 +2251,16 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM {
         // info calls so that types are up to date; erasure may add lateINTERFACE to traits
         hostSymbol.info ; methodOwner.info
 
-        def isInterfaceCall(sym: Symbol) = (
-             sym.isInterface && methodOwner != ObjectClass
+        def needsInterfaceCall(sym: Symbol) = (
+             sym.isInterface
           || sym.isJavaDefined && sym.isNonBottomSubClass(ClassfileAnnotationClass)
         )
         // whether to reference the type of the receiver or
-        // the type of the method owner (if not an interface!)
+        // the type of the method owner
         val useMethodOwner = (
              style != Dynamic
-          || !isInterfaceCall(hostSymbol) && isAccessibleFrom(methodOwner, siteSymbol)
           || hostSymbol.isBottomClass
+          || methodOwner == ObjectClass
         )
         val receiver = if (useMethodOwner) methodOwner else hostSymbol
         val jowner   = javaName(receiver)
@@ -2283,11 +2283,11 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM {
         }
 
         style match {
-          case Static(true)                         => dbg("invokespecial");  jcode.invokespecial  (jowner, jname, jtype)
-          case Static(false)                        => dbg("invokestatic");   jcode.invokestatic   (jowner, jname, jtype)
-          case Dynamic if isInterfaceCall(receiver) => dbg("invokinterface"); jcode.invokeinterface(jowner, jname, jtype)
-          case Dynamic                              => dbg("invokevirtual");  jcode.invokevirtual  (jowner, jname, jtype)
-          case SuperCall(_)                         =>
+          case Static(true)                            => dbg("invokespecial");  jcode.invokespecial  (jowner, jname, jtype)
+          case Static(false)                           => dbg("invokestatic");   jcode.invokestatic   (jowner, jname, jtype)
+          case Dynamic if needsInterfaceCall(receiver) => dbg("invokinterface"); jcode.invokeinterface(jowner, jname, jtype)
+          case Dynamic                                 => dbg("invokevirtual");  jcode.invokevirtual  (jowner, jname, jtype)
+          case SuperCall(_)                            =>
             dbg("invokespecial")
             jcode.invokespecial(jowner, jname, jtype)
             initModule()
diff --git a/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala b/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala
index 555c79e75e..557ef925a7 100644
--- a/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala
+++ b/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala
@@ -958,6 +958,7 @@ abstract class Inliners extends SubComponent {
             if(isInlineForbidden)  { rs ::= "is annotated @noinline" }
             if(inc.isSynchronized) { rs ::= "is synchronized method" }
             if(inc.m.bytecodeHasEHs) { rs ::= "bytecode contains exception handlers / finally clause" } // SI-6188
+            if(inc.m.bytecodeHasInvokeDynamic) { rs ::= "bytecode contains invoke dynamic" }
             if(rs.isEmpty) null else rs.mkString("", ", and ", "")
           }
 
diff --git a/src/compiler/scala/tools/nsc/javac/JavaParsers.scala b/src/compiler/scala/tools/nsc/javac/JavaParsers.scala
index cf40fe90fa..f1b1d1a9a7 100644
--- a/src/compiler/scala/tools/nsc/javac/JavaParsers.scala
+++ b/src/compiler/scala/tools/nsc/javac/JavaParsers.scala
@@ -755,13 +755,7 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
       val pos = in.currentPos
       val name = identForType()
       val (statics, body) = typeBody(AT, name)
-      def getValueMethodType(tree: Tree) = tree match {
-        case DefDef(_, nme.value, _, _, tpt, _) => Some(tpt.duplicate)
-        case _ => None
-      }
-      var templ = makeTemplate(annotationParents, body)
-      for (stat <- templ.body; tpt <- getValueMethodType(stat))
-        templ = makeTemplate(annotationParents, makeConstructor(List(tpt)) :: templ.body)
+      val templ = makeTemplate(annotationParents, body)
       addCompanionObject(statics, atPos(pos) {
         ClassDef(mods, name, List(), templ)
       })
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
index 1206748b24..879320c016 100644
--- a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
+++ b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
@@ -136,10 +136,13 @@ abstract class ClassfileParser {
         (in.nextByte.toInt: @switch) match {
           case CONSTANT_UTF8 | CONSTANT_UNICODE =>
             in.skip(in.nextChar)
-          case CONSTANT_CLASS | CONSTANT_STRING =>
+          case CONSTANT_CLASS | CONSTANT_STRING | CONSTANT_METHODTYPE=>
             in.skip(2)
+          case CONSTANT_METHODHANDLE =>
+            in.skip(3)
           case CONSTANT_FIELDREF | CONSTANT_METHODREF | CONSTANT_INTFMETHODREF
-             | CONSTANT_NAMEANDTYPE | CONSTANT_INTEGER | CONSTANT_FLOAT =>
+             | CONSTANT_NAMEANDTYPE | CONSTANT_INTEGER | CONSTANT_FLOAT
+             | CONSTANT_INVOKEDYNAMIC =>
             in.skip(4)
           case CONSTANT_LONG | CONSTANT_DOUBLE =>
             in.skip(8)
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/ICodeReader.scala b/src/compiler/scala/tools/nsc/symtab/classfile/ICodeReader.scala
index 599823b408..80a810703c 100644
--- a/src/compiler/scala/tools/nsc/symtab/classfile/ICodeReader.scala
+++ b/src/compiler/scala/tools/nsc/symtab/classfile/ICodeReader.scala
@@ -501,6 +501,13 @@ abstract class ICodeReader extends ClassfileParser {
             code.emit(UNBOX(toTypeKind(m.info.resultType)))
           else
             code.emit(CALL_METHOD(m, Static(onInstance = false)))
+        case JVM.invokedynamic  =>
+          // TODO, this is just a place holder. A real implementation must parse the class constant entry
+          debuglog("Found JVM invokedynamic instructionm, inserting place holder ICode INVOKE_DYNAMIC.")
+          containsInvokeDynamic = true
+          val poolEntry = in.nextChar
+          in.skip(2)
+          code.emit(INVOKE_DYNAMIC(poolEntry))
 
         case JVM.new_          =>
           code.emit(NEW(REFERENCE(pool.getClassSymbol(in.nextChar))))
@@ -639,6 +646,7 @@ abstract class ICodeReader extends ClassfileParser {
     var containsDUPX = false
     var containsNEW  = false
     var containsEHs  = false
+    var containsInvokeDynamic = false
 
     def emit(i: Instruction) {
       instrs += ((pc, i))
@@ -657,6 +665,7 @@ abstract class ICodeReader extends ClassfileParser {
       val code = new Code(method)
       method.setCode(code)
       method.bytecodeHasEHs = containsEHs
+      method.bytecodeHasInvokeDynamic = containsInvokeDynamic
       var bb = code.startBlock
 
       def makeBasicBlocks: mutable.Map[Int, BasicBlock] =
diff --git a/src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala b/src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala
index 124dd6c995..367825c251 100644
--- a/src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala
+++ b/src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala
@@ -41,26 +41,24 @@ abstract class ExplicitOuter extends InfoTransform
   private def isInner(clazz: Symbol) =
     !clazz.isPackageClass && !clazz.outerClass.isStaticOwner
 
-  private def haveSameOuter(parent: Type, clazz: Symbol) = parent match {
-    case TypeRef(pre, sym, _)   =>
-      val owner = clazz.owner
+  private def haveSameOuter(parent: Type, clazz: Symbol) = {
+    val owner = clazz.owner
+    val parentSym = parent.typeSymbol
 
-      //println(s"have same outer $parent $clazz $sym ${sym.owner} $owner $pre")
-
-      sym.isClass && owner.isClass &&
-      (owner isSubClass sym.owner) &&
-      owner.thisType =:= pre
-
-    case _                      => false
+    parentSym.isClass && owner.isClass &&
+      (owner isSubClass parentSym.owner) &&
+      owner.thisType =:= parent.prefix
   }
 
   /** Does given clazz define an outer field? */
   def hasOuterField(clazz: Symbol) = {
-    val parents = clazz.info.parents
+    val parent = clazz.info.firstParent
 
-    isInner(clazz) && !clazz.isTrait && {
-      parents.isEmpty || !haveSameOuter(parents.head, clazz)
-    }
+    // space optimization: inherit the $outer pointer from the parent class if
+    // we know that it will point to the correct instance.
+    def canReuseParentOuterField = !parent.typeSymbol.isJavaDefined && haveSameOuter(parent, clazz)
+
+    isInner(clazz) && !clazz.isTrait && !canReuseParentOuterField
   }
 
   private def outerField(clazz: Symbol): Symbol = {
@@ -100,6 +98,29 @@ abstract class ExplicitOuter extends InfoTransform
     sym setInfo clazz.outerClass.thisType
   }
 
+  /**
+   * Will the outer accessor of the `clazz` subsume the outer accessor of
+   * `mixin`?
+   *
+   * This arises when an inner object mixes in its companion trait.
+   *
+   * {{{
+   *   class C {
+   *     trait T { C.this }            // C$T$$$outer$ : C
+   *     object T extends T { C.this } // C$T$$$outer$ : C.this.type
+   *   }
+   * }}}
+   *
+   * See SI-7242.
+   }}
+   */
+  private def skipMixinOuterAccessor(clazz: Symbol, mixin: Symbol) = {
+    // Reliant on the current scheme for name expansion, the expanded name
+    // of the outer accessors in a trait and its companion object are the same.
+    // If the assumption is one day falsified, run/t7424.scala will let us know.
+    clazz.fullName == mixin.fullName
+  }
+
   /** <p>
    *    The type transformation method:
    *  </p>
@@ -162,10 +183,14 @@ abstract class ExplicitOuter extends InfoTransform
         for (mc <- clazz.mixinClasses) {
           val mixinOuterAcc: Symbol = exitingExplicitOuter(outerAccessor(mc))
           if (mixinOuterAcc != NoSymbol) {
-            if (decls1 eq decls) decls1 = decls.cloneScope
-            val newAcc = mixinOuterAcc.cloneSymbol(clazz, mixinOuterAcc.flags & ~DEFERRED)
-            newAcc setInfo (clazz.thisType memberType mixinOuterAcc)
-            decls1 enter newAcc
+            if (skipMixinOuterAccessor(clazz, mc))
+              debuglog(s"Reusing outer accessor symbol of $clazz for the mixin outer accessor of $mc")
+            else {
+              if (decls1 eq decls) decls1 = decls.cloneScope
+              val newAcc = mixinOuterAcc.cloneSymbol(clazz, mixinOuterAcc.flags & ~DEFERRED)
+              newAcc setInfo (clazz.thisType memberType mixinOuterAcc)
+              decls1 enter newAcc
+            }
           }
         }
       }
@@ -370,6 +395,7 @@ abstract class ExplicitOuter extends InfoTransform
       val outerAcc    = outerAccessor(mixinClass) overridingSymbol currentClass
       def mixinPrefix = (currentClass.thisType baseType mixinClass).prefix
       assert(outerAcc != NoSymbol, "No outer accessor for inner mixin " + mixinClass + " in " + currentClass)
+      assert(outerAcc.alternatives.size == 1, s"Multiple outer accessors match inner mixin $mixinClass in $currentClass : ${outerAcc.alternatives.map(_.defString)}")
       // I added the mixinPrefix.typeArgs.nonEmpty condition to address the
       // crash in SI-4970.  I feel quite sure this can be improved.
       val path = (
@@ -404,7 +430,7 @@ abstract class ExplicitOuter extends InfoTransform
               }
               if (!currentClass.isTrait)
                 for (mc <- currentClass.mixinClasses)
-                  if (outerAccessor(mc) != NoSymbol)
+                  if (outerAccessor(mc) != NoSymbol && !skipMixinOuterAccessor(currentClass, mc))
                     newDefs += mixinOuterAccessorDef(mc)
             }
           }
diff --git a/src/compiler/scala/tools/nsc/transform/UnCurry.scala b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
index 8fd1df7cea..11bd0665b1 100644
--- a/src/compiler/scala/tools/nsc/transform/UnCurry.scala
+++ b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
@@ -347,10 +347,14 @@ abstract class UnCurry extends InfoTransform
         }
         else {
           log(s"Argument '$arg' at line ${arg.pos.safeLine} is $formal from ${fun.fullName}")
+          def canUseDirectly(recv: Tree) = (
+               recv.tpe.typeSymbol.isSubClass(FunctionClass(0))
+            && treeInfo.isExprSafeToInline(recv)
+          )
           arg match {
             // don't add a thunk for by-name argument if argument already is an application of
             // a Function0. We can then remove the application and use the existing Function0.
-            case Apply(Select(recv, nme.apply), Nil) if recv.tpe.typeSymbol isSubClass FunctionClass(0) =>
+            case Apply(Select(recv, nme.apply), Nil) if canUseDirectly(recv) =>
               recv
             case _ =>
               newFunction0(arg)
diff --git a/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala b/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala
index 0371df3b10..92b7700c04 100644
--- a/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala
+++ b/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala
@@ -573,6 +573,7 @@ trait ScalaLogic extends Interface with Logic with TreeAndTypeAnalysis {
         assert(tp.isInstanceOf[SingletonType])
         val toString = tp match {
           case ConstantType(c) => c.escapedStringValue
+          case _ if tp.typeSymbol.isModuleClass => tp.typeSymbol.name.toString
           case _ => tp.toString
         }
         Const.unique(tp, new ValueConst(tp, tp.widen, toString))
diff --git a/src/compiler/scala/tools/nsc/transform/patmat/MatchOptimization.scala b/src/compiler/scala/tools/nsc/transform/patmat/MatchOptimization.scala
index 125e9a3b65..31b04d0bd6 100644
--- a/src/compiler/scala/tools/nsc/transform/patmat/MatchOptimization.scala
+++ b/src/compiler/scala/tools/nsc/transform/patmat/MatchOptimization.scala
@@ -15,9 +15,9 @@ import scala.reflect.internal.util.Position
 /** Optimize and analyze matches based on their TreeMaker-representation.
  *
  * The patmat translation doesn't rely on this, so it could be disabled in principle.
- *
- * TODO: split out match analysis
+ *  - well, not quite: the backend crashes if we emit duplicates in switches (e.g. SI-7290)
  */
+// TODO: split out match analysis
 trait MatchOptimization extends MatchTreeMaking with MatchAnalysis {
   import global._
   import global.definitions._
@@ -435,7 +435,7 @@ trait MatchOptimization extends MatchTreeMaking with MatchAnalysis {
               case SwitchableTreeMaker(pattern) :: GuardAndBodyTreeMakers(guard, body) =>
                 Some(CaseDef(pattern, guard, body))
               // alternatives
-              case AlternativesTreeMaker(_, altss, _) :: GuardAndBodyTreeMakers(guard, body) if alternativesSupported =>
+              case AlternativesTreeMaker(_, altss, pos) :: GuardAndBodyTreeMakers(guard, body) if alternativesSupported =>
                 val switchableAlts = altss map {
                   case SwitchableTreeMaker(pattern) :: Nil =>
                     Some(pattern)
@@ -445,7 +445,17 @@ trait MatchOptimization extends MatchTreeMaking with MatchAnalysis {
 
                 // succeed if they were all switchable
                 sequence(switchableAlts) map { switchableAlts =>
-                  CaseDef(Alternative(switchableAlts), guard, body)
+                  def extractConst(t: Tree) = t match {
+                    case Literal(const) => const
+                    case _              => t
+                  }
+                  // SI-7290 Discard duplicate alternatives that would crash the backend
+                  val distinctAlts = distinctBy(switchableAlts)(extractConst)
+                  if (distinctAlts.size < switchableAlts.size) {
+                    val duplicated = switchableAlts.groupBy(extractConst).flatMap(_._2.drop(1).take(1)) // report the first duplicated
+                    global.currentUnit.warning(pos, s"Pattern contains duplicate alternatives: ${duplicated.mkString(", ")}")
+                  }
+                  CaseDef(Alternative(distinctAlts), guard, body)
                 }
               case _ =>
                 // debug.patmat("can't emit switch for "+ makers)
diff --git a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
index d5ecb687b0..6921f8ce27 100644
--- a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
@@ -499,7 +499,7 @@ trait NamesDefaults { self: Analyzer =>
         // disable conforms as a view...
         val errsBefore = reporter.ERROR.count
         try typer.silent { tpr =>
-          val res = tpr.typed(arg, subst(paramtpe))
+          val res = tpr.typed(arg.duplicate, subst(paramtpe))
           // better warning for SI-5044: if `silent` was not actually silent give a hint to the user
           // [H]: the reason why `silent` is not silent is because the cyclic reference exception is
           // thrown in a context completely different from `context` here. The exception happens while
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 1f03a80008..7436a244bd 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1332,8 +1332,7 @@ trait Typers extends Adaptations with Tags {
     def adaptToMemberWithArgs(tree: Tree, qual: Tree, name: Name, mode: Mode, reportAmbiguous: Boolean, saveErrors: Boolean): Tree = {
       def onError(reportError: => Tree): Tree = context.tree match {
           case Apply(tree1, args) if (tree1 eq tree) && args.nonEmpty =>
-          ( silent   (_.typedArgs(args, mode))
-                 map (_.asInstanceOf[List[Tree]])
+          ( silent   (_.typedArgs(args.map(_.duplicate), mode))
               filter (xs => !(xs exists (_.isErrorTyped)))
                  map (xs => adaptToArguments(qual, name, xs, WildcardType, reportAmbiguous, saveErrors))
               orElse ( _ => reportError)
@@ -4380,6 +4379,12 @@ trait Typers extends Adaptations with Tags {
           treeCopy.New(tree, tpt1).setType(tp)
       }
 
+      def functionTypeWildcard(tree: Tree, arity: Int): Type = {
+        val tp = functionType(List.fill(arity)(WildcardType), WildcardType)
+        if (tp == NoType) MaxFunctionArityError(tree)
+        tp
+      }
+
       def typedEta(expr1: Tree): Tree = expr1.tpe match {
         case TypeRef(_, ByNameParamClass, _) =>
           val expr2 = Function(List(), expr1) setPos expr1.pos
@@ -4391,10 +4396,10 @@ trait Typers extends Adaptations with Tags {
           typed1(expr2, mode, pt)
         case PolyType(_, MethodType(formals, _)) =>
           if (isFunctionType(pt)) expr1
-          else adapt(expr1, mode, functionType(formals map (t => WildcardType), WildcardType))
+          else adapt(expr1, mode, functionTypeWildcard(expr1, formals.length))
         case MethodType(formals, _) =>
           if (isFunctionType(pt)) expr1
-          else adapt(expr1, mode, functionType(formals map (t => WildcardType), WildcardType))
+          else adapt(expr1, mode, functionTypeWildcard(expr1, formals.length))
         case ErrorType =>
           expr1
         case _ =>
@@ -4706,7 +4711,7 @@ trait Typers extends Adaptations with Tags {
                 atPos(tree.pos)(gen.convertToSelectFromType(qual, name)) match {
                   case EmptyTree => None
                   case tree1     => Some(typed1(tree1, mode, pt))
-            }
+                }
               }
               else None
             )
diff --git a/src/compiler/scala/tools/nsc/util/SimpleTracer.scala b/src/compiler/scala/tools/nsc/util/SimpleTracer.scala
index 6997dbd402..4e1cf02a6e 100644
--- a/src/compiler/scala/tools/nsc/util/SimpleTracer.scala
+++ b/src/compiler/scala/tools/nsc/util/SimpleTracer.scala
@@ -10,7 +10,7 @@ import java.io.PrintStream
  *  @param enabled: A condition that must be true for trace info to be produced.
  */
 class SimpleTracer(out: PrintStream, enabled: Boolean = true) {
-  def apply[T](msg: String)(value: T): T = {
+  def apply[T](msg: => String)(value: T): T = {
     if (enabled) out.println(msg+value)
     value
   }