From e5b3a8a6b49dd4ab333781e3e7ce595ba14b06eb Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Tue, 13 Feb 2007 22:06:58 +0000
Subject: changed tuple syntax to (...)

---
 src/compiler/scala/tools/ant/Scalac.scala          |   2 +-
 src/compiler/scala/tools/nsc/Global.scala          |   4 +-
 src/compiler/scala/tools/nsc/Interpreter.scala     |   2 +-
 src/compiler/scala/tools/nsc/ast/TreeGen.scala     |   5 +-
 .../scala/tools/nsc/ast/TreePrinters.scala         |   2 +-
 src/compiler/scala/tools/nsc/ast/Trees.scala       |  10 +-
 .../scala/tools/nsc/ast/parser/MarkupParsers.scala |   2 +-
 .../scala/tools/nsc/ast/parser/Parsers.scala       | 313 +++++++--------------
 .../scala/tools/nsc/ast/parser/TreeBuilder.scala   |  48 ++--
 .../scala/tools/nsc/backend/icode/GenICode.scala   |  30 +-
 .../scala/tools/nsc/backend/icode/Members.scala    |   2 +-
 .../scala/tools/nsc/backend/jvm/GenJVM.scala       |  78 ++---
 .../scala/tools/nsc/backend/msil/GenMSIL.scala     |  24 +-
 .../scala/tools/nsc/matching/PatternMatchers.scala |   4 +-
 .../scala/tools/nsc/matching/PatternNodes.scala    |   8 +-
 .../scala/tools/nsc/symtab/SymbolLoaders.scala     |   4 +-
 src/compiler/scala/tools/nsc/symtab/Symbols.scala  |   2 +-
 src/compiler/scala/tools/nsc/symtab/Types.scala    | 152 +++++-----
 .../nsc/symtab/classfile/ClassfileParser.scala     |   6 +-
 .../scala/tools/nsc/symtab/classfile/Pickler.scala |  12 +-
 .../tools/nsc/symtab/classfile/UnPickler.scala     |   4 +-
 .../tools/nsc/typechecker/ConstantFolder.scala     |  24 +-
 .../scala/tools/nsc/typechecker/Contexts.scala     |  10 +-
 .../scala/tools/nsc/typechecker/Infer.scala        |  48 ++--
 .../scala/tools/nsc/typechecker/Namers.scala       |  14 +-
 .../scala/tools/nsc/typechecker/RefChecks.scala    |  10 +-
 .../tools/nsc/typechecker/SuperAccessors.scala     |   4 +-
 .../tools/nsc/typechecker/SyntheticMethods.scala   |   2 +-
 .../scala/tools/nsc/typechecker/Typers.scala       |  68 ++---
 29 files changed, 394 insertions(+), 500 deletions(-)

(limited to 'src/compiler')

diff --git a/src/compiler/scala/tools/ant/Scalac.scala b/src/compiler/scala/tools/ant/Scalac.scala
index b16aacd2dd..7400cf610e 100644
--- a/src/compiler/scala/tools/ant/Scalac.scala
+++ b/src/compiler/scala/tools/ant/Scalac.scala
@@ -619,7 +619,7 @@ class Scalac extends MatchingTask {
 
   /** Performs the compilation. */
   override def execute() = {
-    val {settings, sourceFiles} = initialize
+    val Pair(settings, sourceFiles) = initialize
     val reporter = new ConsoleReporter(settings)
 
     // Compiles the actual code
diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 58f088002b..7636c39e9b 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -507,7 +507,7 @@ class Global(var settings: Settings, var reporter: Reporter) extends SymbolTable
         showDef(newTermName(settings.Xshowobj.value), true)
 
       if (reporter.hasErrors) {
-        for (val {sym, file} <- symSource.elements) {
+        for (val Pair(sym, file) <- symSource.elements) {
           sym.reset(new loaders.SourcefileLoader(file))
           if (sym.isTerm) sym.moduleClass.reset(loaders.moduleClassLoader)
         }
@@ -520,7 +520,7 @@ class Global(var settings: Settings, var reporter: Reporter) extends SymbolTable
           warning("there were unchecked warnings; re-run with -unchecked for details")
         }
       }
-      for (val {sym, file} <- symSource.elements) resetPackageClass(sym.owner)
+      for (val Pair(sym, file) <- symSource.elements) resetPackageClass(sym.owner)
       //units foreach (.clear())
       informTime("total", startTime)
     }
diff --git a/src/compiler/scala/tools/nsc/Interpreter.scala b/src/compiler/scala/tools/nsc/Interpreter.scala
index 119b68e5d3..6ea4d43143 100644
--- a/src/compiler/scala/tools/nsc/Interpreter.scala
+++ b/src/compiler/scala/tools/nsc/Interpreter.scala
@@ -102,7 +102,7 @@ class Interpreter(val settings: Settings, reporter: Reporter, out: PrintWriter)
   settings.outdir.value = classfilePath.getPath
 
   /** the compiler to compile expressions with */
-  val compiler = new Global(settings, reporter)
+  val compiler: Global = new Global(settings, reporter)
 
   /** the compiler's classpath, as URL's */
   val compilerClasspath: List[URL] =
diff --git a/src/compiler/scala/tools/nsc/ast/TreeGen.scala b/src/compiler/scala/tools/nsc/ast/TreeGen.scala
index 8be11e40b4..f639fc3c44 100644
--- a/src/compiler/scala/tools/nsc/ast/TreeGen.scala
+++ b/src/compiler/scala/tools/nsc/ast/TreeGen.scala
@@ -164,8 +164,9 @@ abstract class TreeGen {
     mkAttributedRef(definitions.NilModule)
 
   /** Builds a pair */
-  def mkNewPair(left: Tree, right: Tree) =
-    New(Apply(mkAttributedRef(definitions.TupleClass(2)), List(left, right)))
+  def mkTuple(elems: List[Tree]): Tree =
+    if (elems.isEmpty) Literal(())
+    else New(TypeTree(definitions.TupleClass(elems.length).tpe), List(elems))
 
   def mkCached(cvar: Symbol, expr: Tree): Tree = {
     val cvarRef = if (cvar.owner.isClass) Select(This(cvar.owner), cvar) else Ident(cvar)
diff --git a/src/compiler/scala/tools/nsc/ast/TreePrinters.scala b/src/compiler/scala/tools/nsc/ast/TreePrinters.scala
index 55b4bb0e2c..5d2afcc332 100644
--- a/src/compiler/scala/tools/nsc/ast/TreePrinters.scala
+++ b/src/compiler/scala/tools/nsc/ast/TreePrinters.scala
@@ -167,7 +167,7 @@ abstract class TreePrinters {
           print(symName(tree, name)); printRow(params, "(", ",", ")"); printBlock(rhs)
 
         case Import(expr, selectors) =>
-          def selectorToString(s: {Name, Name}): String =
+          def selectorToString(s: Pair[Name, Name]): String =
             if (s._1 == nme.WILDCARD || s._1 == s._2) s._1.toString()
             else s._1.toString() + "=>" + s._2.toString()
           print("import "); print(expr)
diff --git a/src/compiler/scala/tools/nsc/ast/Trees.scala b/src/compiler/scala/tools/nsc/ast/Trees.scala
index a7843c9fad..abcbcf3cf6 100644
--- a/src/compiler/scala/tools/nsc/ast/Trees.scala
+++ b/src/compiler/scala/tools/nsc/ast/Trees.scala
@@ -407,7 +407,7 @@ trait Trees requires Global {
    *  @param expr
    *  @param selectors
    */
-  case class Import(expr: Tree, selectors: List[{Name, Name}])
+  case class Import(expr: Tree, selectors: List[Pair[Name, Name]])
        extends SymTree
 
   /** Annotation application (constructor arguments + name-value pairs) */
@@ -749,7 +749,7 @@ trait Trees requires Global {
     def AbsTypeDef(tree: Tree, mods: Modifiers, name: Name, lo: Tree, hi: Tree): AbsTypeDef
     def AliasTypeDef(tree: Tree, mods: Modifiers, name: Name, tparams: List[AbsTypeDef], rhs: Tree): AliasTypeDef
     def LabelDef(tree: Tree, name: Name, params: List[Ident], rhs: Tree): LabelDef
-    def Import(tree: Tree, expr: Tree, selectors: List[{Name, Name}]): Import
+    def Import(tree: Tree, expr: Tree, selectors: List[Pair[Name, Name]]): Import
     def Annotation(tree: Tree, constr: Tree, elements: List[Tree]): Annotation
     def DocDef(tree: Tree, comment: String, definition: Tree): DocDef
     def Template(tree: Tree, parents: List[Tree], body: List[Tree]): Template
@@ -804,7 +804,7 @@ trait Trees requires Global {
       new AliasTypeDef(mods, name, tparams, rhs).copyAttrs(tree)
     def LabelDef(tree: Tree, name: Name, params: List[Ident], rhs: Tree) =
       new LabelDef(name, params, rhs).copyAttrs(tree)
-    def Import(tree: Tree, expr: Tree, selectors: List[{Name, Name}]) =
+    def Import(tree: Tree, expr: Tree, selectors: List[Pair[Name, Name]]) =
       new Import(expr, selectors).copyAttrs(tree)
     def Annotation(tree: Tree, constr: Tree, elements: List[Tree]) =
       new Annotation(constr, elements)
@@ -921,7 +921,7 @@ trait Trees requires Global {
       if (name0 == name) && (params0 == params) && (rhs0 == rhs) => t
       case _ => copy.LabelDef(tree, name, params, rhs)
     }
-    def Import(tree: Tree, expr: Tree, selectors: List[{Name, Name}]) = tree match {
+    def Import(tree: Tree, expr: Tree, selectors: List[Pair[Name, Name]]) = tree match {
       case t @ Import(expr0, selectors0)
       if (expr0 == expr) && (selectors0 == selectors) => t
       case _ => copy.Import(tree, expr, selectors)
@@ -1287,7 +1287,7 @@ trait Trees requires Global {
         traverse(expr)
       case Annotation(constr, elements) =>
         traverse(constr); traverseTrees(elements)
-      case Annotated(constr: Tree, elements: List[Tree], arg: Tree) =>
+      case Annotated(constr, elements, arg) =>
         traverse(constr); traverseTrees(elements); traverse(arg)
       case DocDef(comment, definition) =>
         traverse(definition)
diff --git a/src/compiler/scala/tools/nsc/ast/parser/MarkupParsers.scala b/src/compiler/scala/tools/nsc/ast/parser/MarkupParsers.scala
index 4b85bd2b6d..4e1d73b53f 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/MarkupParsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/MarkupParsers.scala
@@ -575,7 +575,7 @@ class MarkupParser(unit: CompilationUnit, s: Scanner, p: Parser, presWS: boolean
    */
   def xScalaPatterns: List[Tree] = {
     sync;
-    val b = p.patterns(true, false);
+    val b = p.patterns(true);
     if (/*s.*/token != RBRACE) {
       reportSyntaxError(" expected end of Scala patterns");
     }
diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index f85ffc8b4e..dfbc330145 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -256,16 +256,11 @@ trait Parsers requires SyntaxAnalyzer {
 
     /** Convert tree to formal parameter list
     */
-    def convertToParams(t: Tree): List[ValDef] = t match {
-      case Function(params, TypeTree()) =>
-        params
-      case Ident(_) | Typed(Ident(_), _) =>
-        List(convertToParam(t))
-      case Literal(c) if c.tag == UnitTag =>
-        Nil
+    def convertToParams(tree: Tree): List[ValDef] = tree match {
+      case Parens(ts) =>
+        ts map convertToParam
       case _ =>
-        syntaxError(t.pos, "malformed formal parameter list", false)
-        Nil
+        List(convertToParam(tree))
     }
 
     /** Convert tree to formal parameter
@@ -278,7 +273,9 @@ trait Parsers requires SyntaxAnalyzer {
           case Typed(Ident(name), tpe) =>
             ValDef(Modifiers(Flags.PARAM), name, tpe, EmptyTree)
           case _ =>
+            Console.println("CTP "+tree) //debug
             syntaxError(tree.pos, "not a legal formal parameter", false)
+            throw new Error()
             ValDef(Modifiers(Flags.PARAM), nme.ERROR, errorTypeTree, EmptyTree)
         }
       }
@@ -316,7 +313,7 @@ trait Parsers requires SyntaxAnalyzer {
 
       Function(
         List(ValDef(Modifiers(Flags.PARAM), pname, TypeTree(), EmptyTree)),
-        wrapLiftedGenerators(insertParam(tree)))
+        insertParam(tree))
     }
 
 /////// OPERAND/OPERATOR STACK /////////////////////////////////////////////////
@@ -568,13 +565,15 @@ trait Parsers requires SyntaxAnalyzer {
       }
       else TypeTree()
 
-    /** Types ::= Type {`,' Type}
-    */
-    def types(): List[Tree] = {
-      val ts = new ListBuffer[Tree] + typ()
+    /** Types ::= Type {`,' Type} [`,']
+     *  ArgTypePatterns ::=  ArgTypePattern {`,' ArgTypePattern} [`,']
+     */
+    def types(isPattern: boolean): List[Tree] = {
+      val ts = new ListBuffer[Tree] + argType(isPattern)
       while (in.token == COMMA) {
         in.nextToken()
-        ts += typ()
+        if (in.token == RPAREN) return List(makeTupleType(ts.toList, false))
+        ts += argType(isPattern)
       }
       ts.toList
     }
@@ -584,14 +583,14 @@ trait Parsers requires SyntaxAnalyzer {
     final val LeftOp = 1    // left associative
     final val RightOp = 2   // right associative
 
-    /** Type ::= InfixType `=>' Type
-     *         | `(' [Types | `=>' Type] `)' `=>' Type
-     *         | InfixType
+    /** Type ::= InfixType [`=>' Type]
+     *         | (`=>' Type) `=>' Type
+     *         | `(' `)' `=>' Type
      */
     def typ(): Tree = {
       val t =
         if (in.token == LPAREN) {
-          in.nextToken()
+          val pos = in.skipToken()
           if (in.token == RPAREN) {
             in.nextToken()
             atPos(accept(ARROW)) { makeFunctionTypeTree(List(), typ()) }
@@ -601,24 +600,15 @@ trait Parsers requires SyntaxAnalyzer {
             accept(RPAREN)
             atPos(accept(ARROW)) { makeByNameFunctionTypeTree(t0, typ()) }
           } else {
-            val pos = in.currentPos
-            val t0 = typ()
-            if (in.token == COMMA) {
-              in.nextToken()
-              val ts = t0 :: types()
-              accept(RPAREN)
-              checkSize("function arguments", ts.length, definitions.MaxFunctionArity)
-              atPos (accept(ARROW)) { makeFunctionTypeTree(ts, typ()) }
-            } else {
-              accept(RPAREN)
-              infixTypeRest(pos, t0, false, FirstOp)
-            }
+            val ts = types(false)
+            accept(RPAREN)
+            if (in.token == ARROW) atPos(in.skipToken()) { makeFunctionTypeTree(ts, typ()) }
+            else infixTypeRest(pos, makeTupleType(ts, true), false, FirstOp)
           }
         } else {
           infixType(false, FirstOp)
         }
-      if (in.token == ARROW) atPos(in.skipToken()) {
-        makeFunctionTypeTree(List(t), typ()) }
+      if (in.token == ARROW) atPos(in.skipToken()) { makeFunctionTypeTree(List(t), typ()) }
       else t
     }
 
@@ -667,35 +657,24 @@ trait Parsers requires SyntaxAnalyzer {
      *                     |   SimpleType1 `#' Id
      *                     |   StableId
      *                     |   Path `.' type
-     *                     |   `(' Type `)'
-     *                     |   `{' [Type `,' [Types [`,']]] `}'
-     * SimpleTypePattern  ::=  SimpleTypePattern1 [TypePatternArgs]
-     * SimpleTypePattern1 ::=  SimpleTypePattern1 "#" Id
+     *                     |   `(' Types `)'
+     * SimpleTypePattern  ::=  Annotations SimpleTypePattern1
+     * SimpleTypePattern1 ::=  SimpleTypePattern2 [TypePatternArgs]
+     * SimpleTypePattern2 ::=  SimpleTypePattern2 "#" Id
      *                     |   StableId
      *                     |   Path `.' type
-     *                     |   `{' [ArgTypePattern `,' [ArgTypePatterns [`,']]] `}'
+     *                     |   `(' ArgTypePattern {`,' ArgTypePattern} [`,'] `)'
      */
     def simpleType(isPattern: boolean): Tree = {
       val annots = if (settings.Xplugtypes.value) typeAttributes()
                    else annotations()
       val pos = in.currentPos
       var t: Tree =
-        if (in.token == LPAREN && !isPattern) {
+        if (in.token == LPAREN) {
           in.nextToken()
-          val t = typ()
+          val ts = types(isPattern)
           accept(RPAREN)
-          t
-        } else if (in.token == LBRACE) {
-          in.nextToken()
-          val ts = if (in.token == RBRACE) List()
-                   else {
-                     val t1 = argType(isPattern)
-                     accept(COMMA)
-                     t1 :: (if (in.token == RBRACE) List() else argTypes(isPattern, true))
-                   }
-          checkSize("tuple elements", ts.length, definitions.MaxTupleArity)
-          accept(RBRACE)
-          makeTupleType(ts, false)
+          atPos(pos) { makeTupleType(ts, true) }
         } else {
           val r = path(false, true)
           val x = r match {
@@ -723,29 +702,16 @@ trait Parsers requires SyntaxAnalyzer {
       else (t /: annots) (makeAnnotated)
     }
 
-    /** TypeArgs        ::= `[' ArgTypes `]'
-     *  TypePatternArgs ::= '[' ArgTypePatterns `]'
+    /** TypeArgs        ::= `[' ArgType {`,' ArgType} `]'
+     *  TypePatternArgs ::= '[' ArgTypePattern {`,' ArgTypePattern} `]'
      */
     def typeArgs(isPattern: boolean): List[Tree] = {
       accept(LBRACKET)
-      val ts = argTypes(isPattern, false)
+      val ts = types(isPattern)
       accept(RBRACKET)
       ts
     }
 
-    /** ArgTypes        ::= ArgType {`,' ArgType}
-     *  ArgTypePatterns ::= ArgTypePattern {`,' ArgTypePattern}
-     */
-    def argTypes(isPattern: boolean, trailingComma: boolean): List[Tree] = {
-      val ts = new ListBuffer[Tree] + argType(isPattern)
-      while (in.token == COMMA) {
-        in.nextToken()
-        if (!trailingComma || in.token != RBRACE)
-          ts += argType(isPattern)
-      }
-      ts.toList
-    }
-
     /** ArgType       ::= Type
      *  ArgTypePattern ::=  varid
      *                 |  `_'
@@ -764,6 +730,7 @@ trait Parsers requires SyntaxAnalyzer {
 
 //////// EXPRESSIONS ////////////////////////////////////////////////////////
 
+/*
     // XX_LIFTED
     var liftedGenerators = new collection.mutable.ListBuffer[ValFrom]
 
@@ -797,7 +764,7 @@ trait Parsers requires SyntaxAnalyzer {
       liftedGenerators = savedLiftedGenerators
       t
     }
-
+*/
     /** EqualsExpr ::= `=' Expr
      */
     def equalsExpr(): Tree = {
@@ -805,19 +772,20 @@ trait Parsers requires SyntaxAnalyzer {
       expr()
     }
 
-    /** Exprs ::= Expr {`,' Expr} [ `:' `_' `*' ]
+    /** Exprs ::= Expr {`,' Expr} [`,']
      */
-    def argExprs(): List[Tree] = {
+    def exprs(): List[Tree] = {
       val ts = new ListBuffer[Tree] + argExpr()
       while (in.token == COMMA) {
-        in.nextToken(); ts += argExpr()
+        in.nextToken();
+        if (in.token == RPAREN) return List(makeTupleTerm(ts.toList, false))
+        ts += argExpr()
       }
       ts.toList
     }
 
     /** expression modifiles */
 
-    final val IsArgument     = 1
     final val IsInBlock      = 2
     final val ClosureOK      = 4
 
@@ -835,29 +803,27 @@ trait Parsers requires SyntaxAnalyzer {
      *               | [SimpleExpr `.'] Id `=' Expr
      *               | SimpleExpr ArgumentExprs `=' Expr
      *               | `.' SimpleExpr
-     *               | PostfixExpr [`:' CompoundType]
+     *               | PostfixExpr [`:' (CompoundType | `_' `*')]
      *               | PostfixExpr match [`!'] `{' CaseClauses `}'
      *               | MethodClosure
      *  Bindings   ::= `(' [Binding {`,' Binding}] `)'
      *  Binding    ::= Id [`:' Type]
      */
     def expr(): Tree =
-      liftingScope(exprImpl(ClosureOK))
+      exprImpl(ClosureOK)
 
     def blockStatExpr(): Tree = {
-      liftingScope(exprImpl(IsInBlock | ClosureOK))
+      exprImpl(IsInBlock | ClosureOK)
     }
 
     def argExpr(): Tree = {
-      exprImpl(IsArgument | ClosureOK)
+      exprImpl(ClosureOK)
     }
 
     def localExpr(): Tree = {
       exprImpl(ClosureOK)
     }
 
-    def expr1(): Tree = exprImpl(0)
-
     private def exprImpl(mode: int): Tree = in.token match {
       case IF =>
         val pos = in.skipToken()
@@ -892,7 +858,7 @@ trait Parsers requires SyntaxAnalyzer {
         val lname: Name = unit.fresh.newName("while$")
         val pos = in.skipToken()
         accept(LPAREN)
-        val cond = noLifting(localExpr())
+        val cond = localExpr()
         accept(RPAREN)
         newLinesOpt()
         val body = expr()
@@ -904,7 +870,7 @@ trait Parsers requires SyntaxAnalyzer {
         if (isStatSep) in.nextToken()
         accept(WHILE)
         accept(LPAREN)
-        val cond = noLifting(localExpr())
+        val cond = localExpr()
         accept(RPAREN)
         atPos(pos) { makeDoWhile(lname, body, cond) }
       case FOR =>
@@ -929,7 +895,7 @@ trait Parsers requires SyntaxAnalyzer {
       case DOT =>
         atPos(in.skipToken()) {
           if (isIdent) {
-            liftingScope(makeClosure(simpleExpr()))
+            makeClosure(stripParens(simpleExpr()))
             // Note: makeClosure does some special treatment of liftedGenerators
           } else {
             syntaxErrorOrIncomplete("identifier expected", true)
@@ -945,17 +911,16 @@ trait Parsers requires SyntaxAnalyzer {
             case _ =>
           }
         } else if (in.token == COLON) {
+          t = stripParens(t)
           val pos = in.skipToken()
           val annots = annotations()
-          if ((mode & IsArgument) != 0 && in.token == USCORE) {
+          if (in.token == USCORE) {
             val pos1 = in.skipToken()
             if (isIdent && in.name == nme.STAR) {
               in.nextToken()
               t = atPos(pos) {
                 Typed(t, atPos(pos1) { Ident(nme.WILDCARD_STAR.toTypeName) })
               }
-              if (in.token != RPAREN)
-                syntaxErrorOrIncomplete("`)' expected", false)
             } else {
               syntaxErrorOrIncomplete("`*' expected", true)
             }
@@ -974,7 +939,7 @@ trait Parsers requires SyntaxAnalyzer {
             accept(LBRACE)
             val cases = caseClauses()
             accept(RBRACE)
-            Match(t, cases)
+            Match(stripParens(t), cases)
           }
         }
         if ((mode & ClosureOK) != 0 && in.token == ARROW) {
@@ -982,12 +947,12 @@ trait Parsers requires SyntaxAnalyzer {
             Function(convertToParams(t), if ((mode & IsInBlock) != 0) block() else expr())
           }
         }
-        t
+        stripParens(t)
     }
 
     /** PostfixExpr   ::= [`.'] InfixExpr [Id [NewLine]]
      *  InfixExpr     ::= PrefixExpr
-     *                  | InfixExpr Id [NewLine] (InfixExpr | ArgumentExprs)
+     *                  | InfixExpr Id [NewLine] InfixExpr
      */
     def postfixExpr(): Tree = {
       val base = opstack
@@ -1000,7 +965,7 @@ trait Parsers requires SyntaxAnalyzer {
         ident()
         newLineOptWhenFollowing(isExprIntroToken)
         if (isExprIntro) {
-          top = secondInfixOperandExpr(op)
+          top = prefixExpr()
         } else {
           val topinfo = opstack.head
           opstack = opstack.tail
@@ -1012,17 +977,6 @@ trait Parsers requires SyntaxAnalyzer {
       reduceStack(true, base, top, 0, true)
     }
 
-    def secondInfixOperandExpr(op: Name): Tree =
-      if (in.token == LPAREN && treeInfo.isLeftAssoc(op)) {
-        val pos = in.currentPos
-        val args = argumentExprs()
-        if (args.isEmpty) simpleExprRest(Literal(()) setPos pos, false)
-        else if (args.tail.isEmpty) simpleExprRest(args.head, false)
-        else ArgumentExprs(args)
-      } else {
-        prefixExpr()
-      }
-
     /** PrefixExpr   ::= [`-' | `+' | `~' | `!' | `&' | `/'] SimpleExpr
     */
     def prefixExpr(): Tree =
@@ -1030,16 +984,16 @@ trait Parsers requires SyntaxAnalyzer {
         val name = ident()
         in.token match {
           case INTLIT | LONGLIT | FLOATLIT | DOUBLELIT => literal(false, true)
-          case _ => atPos(in.currentPos) { Select(simpleExpr(), name) }
+          case _ => atPos(in.currentPos) { Select(stripParens(simpleExpr()), name) }
         }
       } else if (isIdent && (in.name == PLUS || in.name == TILDE || in.name == BANG)) {
         val pos = in.currentPos
         val name = ident()
-        atPos(pos) { Select(simpleExpr(), name) }
+        atPos(pos) { Select(stripParens(simpleExpr()), name) }
       } else if (isIdent && in.name == AMP) {
         val pos = in.currentPos
         val name = ident()
-        atPos(pos) { Typed(simpleExpr(), Function(List(), EmptyTree)) }
+        atPos(pos) { Typed(stripParens(simpleExpr()), Function(List(), EmptyTree)) }
 /* XX-LIFTING
       } else if (settings.Xexperimental.value && isIdent && in.name == SLASH) {
         val pos = in.skipToken()
@@ -1059,6 +1013,7 @@ trait Parsers requires SyntaxAnalyzer {
      *                | StableId `.' class
      *                | `(' [Expr] `)'
      *                | BlockExpr
+     *                | new Template
      *                | SimpleExpr `.' Id
      *                | SimpleExpr TypeArgs
      *                | SimpleExpr1 ArgumentExprs
@@ -1076,28 +1031,9 @@ trait Parsers requires SyntaxAnalyzer {
           t = path(true, false)
         case LPAREN =>
           val pos = in.skipToken()
-          if (in.token == RPAREN) {
-            in.nextToken()
-            t = Literal(()).setPos(pos)
-          } else {
-            t = localExpr()
-            if (in.token == COMMA) {
-              val commapos = in.skipToken()
-              val ts = new ListBuffer[Tree] + t ++ argExprs()
-              accept(RPAREN)
-              if (in.token == ARROW) {
-                t = atPos(pos) {
-                  Function(ts.toList map convertToParam, TypeTree())
-                }
-              } else if(in.token == EOF) {
-                incompleteInputError("`=>' expected")
-              } else {
-                syntaxError(commapos, "`)' expected", false)
-              }
-            } else {
-              accept(RPAREN)
-            }
-          }
+          val ts = if (in.token == RPAREN) List() else exprs()
+          accept(RPAREN)
+          t = Parens(ts)
         case LBRACE =>
           t = blockExpr()
         case NEW =>
@@ -1130,7 +1066,7 @@ trait Parsers requires SyntaxAnalyzer {
 
     def simpleExprRest(t: Tree, isNew: boolean): Tree = in.token match {
       case DOT =>
-        simpleExprRest(atPos(in.skipToken()) { selector(t) }, false)
+        simpleExprRest(atPos(in.skipToken()) { selector(stripParens(t)) }, false)
       case LBRACKET =>
         t match {
           case Ident(_) | Select(_, _) =>
@@ -1139,7 +1075,7 @@ trait Parsers requires SyntaxAnalyzer {
             t
         }
       case LPAREN | LBRACE if (!isNew) =>
-        simpleExprRest(atPos(in.currentPos) { Apply(t, argumentExprs()) }, false)
+        simpleExprRest(atPos(in.currentPos) { Apply(stripParens(t), argumentExprs()) }, false)
       case _ =>
         t
     }
@@ -1152,7 +1088,7 @@ trait Parsers requires SyntaxAnalyzer {
         List(blockExpr())
       } else {
         accept(LPAREN)
-        val ts = if (in.token == RPAREN) List() else argExprs()
+        val ts = if (in.token == RPAREN) List() else exprs()
         accept(RPAREN)
         ts
       }
@@ -1163,18 +1099,16 @@ trait Parsers requires SyntaxAnalyzer {
     def blockExpr(): Tree = {
       val res = atPos(accept(LBRACE)) {
         if (in.token == CASE) makeVisitor(caseClauses(), true)
-        else blockOrTuple(true)
+        else block()
       }
       accept(RBRACE)
       res
     }
 
     /** Block ::= BlockStatSeq
-     *  Tuple ::= [Expr1 `,' {Expr1 `,'} [Expr1]]
      */
-    def block(): Tree = blockOrTuple(false)
-    def blockOrTuple(tupleOK: boolean): Tree =
-      makeBlock(blockStatSeqOrTuple(tupleOK, new ListBuffer[Tree]))
+    def block(): Tree =
+      makeBlock(blockStatSeq(new ListBuffer[Tree]))
 
    /** CaseClauses ::= CaseClause {CaseClause}
     */
@@ -1191,7 +1125,7 @@ trait Parsers requires SyntaxAnalyzer {
       atPos(accept(CASE)) {
         val pat = pattern()
         val guard =
-          if (in.token == IF) { in.nextToken(); noLifting(postfixExpr()) }
+          if (in.token == IF) { in.nextToken(); stripParens(postfixExpr()) }
           else EmptyTree
         makeCaseDef(pat, guard, atPos(accept(ARROW))(block()))
       }
@@ -1225,12 +1159,12 @@ trait Parsers requires SyntaxAnalyzer {
 
     /**   Patterns ::= Pattern { `,' Pattern }  */
     /**   SeqPatterns ::= SeqPattern { `,' SeqPattern }  */
-    def patterns(seqOK: boolean, trailingComma: boolean): List[Tree] = {
-      val ts = new ListBuffer[Tree]
-      ts += pattern(seqOK)
+    def patterns(seqOK: boolean): List[Tree] = {
+      val ts = new ListBuffer[Tree] + pattern(seqOK)
       while (in.token == COMMA) {
         in.nextToken();
-        if (!trailingComma || in.token != RBRACE) ts += pattern(seqOK)
+        if (in.token == RPAREN) return List(makeTupleTerm(ts.toList, false))
+        ts += pattern(seqOK)
       }
       ts.toList
     }
@@ -1319,22 +1253,11 @@ trait Parsers requires SyntaxAnalyzer {
         val op = in.name
         opstack = OpInfo(top, op, in.currentPos) :: opstack
         ident()
-        top = secondInfixOperandPattern(op, seqOK)
+        top = simplePattern(seqOK)
       }
-      reduceStack(false, base, top, 0, true)
+      stripParens(reduceStack(false, base, top, 0, true))
     }
 
-    def secondInfixOperandPattern(op: Name, seqOK: boolean): Tree =
-      if (in.token == LPAREN && treeInfo.isLeftAssoc(op)) {
-        val pos = in.currentPos
-        val args = argumentPatterns()
-        if (args.isEmpty) Literal(()) setPos pos
-        else if (args.tail.isEmpty) args.head
-        else ArgumentExprs(args)
-      } else {
-        simplePattern(seqOK)
-      }
-
     /** SimplePattern    ::= varid
      *                    |  `_'
      *                    |  literal
@@ -1373,9 +1296,7 @@ trait Parsers requires SyntaxAnalyzer {
           }
         else */
         if (in.token == LPAREN) {
-          atPos(in.currentPos) { Apply(/*convertToTypeId*/(t), argumentPatterns()) }
-        } else if (in.token == LBRACE) {
-          atPos(in.currentPos) { Apply(/*convertToTypeId*/(t), List(tuplePattern())) }
+          atPos(in.currentPos) { Apply(t, argumentPatterns()) }
         } else t
       case USCORE =>
         atPos(in.skipToken()) { Ident(nme.WILDCARD) }
@@ -1383,15 +1304,9 @@ trait Parsers requires SyntaxAnalyzer {
         literal(true, false)
       case LPAREN =>
         val pos = in.skipToken()
-        val p =
-          //if (false /*disabled, no regexp matching*/ && seqOK) atPos(pos) { makeSequence(patterns(true, false)) }
-          //else
-          if (in.token != RPAREN) pattern(false)
-          else Literal(()).setPos(pos)
+        val ps = if (in.token == RPAREN) List() else patterns(false)
         accept(RPAREN)
-        p
-      case LBRACE =>
-        tuplePattern()
+        Parens(ps)
       case XMLSTART =>
         xmlp.xLiteralPattern
       case _ =>
@@ -1404,24 +1319,11 @@ trait Parsers requires SyntaxAnalyzer {
 
     def argumentPatterns(): List[Tree] = {
       accept(LPAREN)
-      val ps = if (in.token == RPAREN) List() else patterns(true, false)
+      val ps = if (in.token == RPAREN) List() else patterns(true)
       accept(RPAREN)
       ps
     }
 
-    def tuplePattern(): Tree = {
-      in.nextToken()
-      val ts = if (in.token == RBRACE) List()
-               else {
-                 val p1 = pattern()
-                 accept(COMMA)
-                 p1 :: (if (in.token == RBRACE) List() else patterns(false, true))
-               }
-      checkSize("tuple elements", ts.length, definitions.MaxTupleArity)
-      accept(RBRACE)
-      makeTuplePattern(ts)
-    }
-
 ////////// MODIFIERS ////////////////////////////////////////////////////////////
 
     private def normalize(mods: Modifiers): Modifiers =
@@ -1706,7 +1608,7 @@ trait Parsers requires SyntaxAnalyzer {
         def loop: Tree =
           if (in.token == USCORE) {
             in.nextToken()
-            Import(t, List({nme.WILDCARD, null}))
+            Import(t, List(Pair(nme.WILDCARD, null)))
           } else if (in.token == LBRACE) {
             Import(t, importSelectors())
           } else {
@@ -1716,7 +1618,7 @@ trait Parsers requires SyntaxAnalyzer {
               pos = accept(DOT)
               loop
             } else {
-              Import(t, List({name, name}))
+              Import(t, List(Pair(name, name)))
             }
           }
         loop
@@ -1724,8 +1626,8 @@ trait Parsers requires SyntaxAnalyzer {
 
     /** ImportSelectors ::= `{' {ImportSelector `,'} (ImportSelector | `_') `}'
      */
-    def importSelectors(): List[{Name, Name}] = {
-      val names = new ListBuffer[{Name, Name}]
+    def importSelectors(): List[Pair[Name, Name]] = {
+      val names = new ListBuffer[Pair[Name, Name]]
       accept(LBRACE)
       var isLast = importSelector(names)
       while (!isLast && in.token == COMMA) {
@@ -1738,19 +1640,19 @@ trait Parsers requires SyntaxAnalyzer {
 
     /** ImportSelector ::= Id [`=>' Id | `=>' `_']
      */
-    def importSelector(names: ListBuffer[{Name, Name}]): boolean =
+    def importSelector(names: ListBuffer[Pair[Name, Name]]): boolean =
       if (in.token == USCORE) {
-        in.nextToken(); names += {nme.WILDCARD, null}; true
+        in.nextToken(); names += Pair(nme.WILDCARD, null); true
       } else {
         val name = ident()
-        names += {
+        names += Pair(
           name,
           if (in.token == ARROW) {
             in.nextToken()
             if (in.token == USCORE) { in.nextToken(); nme.WILDCARD } else ident()
           } else {
             name
-          }}
+          })
         false
       }
 
@@ -1788,7 +1690,7 @@ trait Parsers requires SyntaxAnalyzer {
       var lhs = new ListBuffer[Tree]
       do {
         in.nextToken()
-        lhs += pattern2(false)
+        lhs += stripParens(pattern2(false))
       } while (in.token == COMMA)
       val tp = typedOpt()
       val rhs =
@@ -1823,9 +1725,9 @@ trait Parsers requires SyntaxAnalyzer {
      */
     def varDefOrDcl(mods: Modifiers): List[Tree] = {
       var newmods = mods | Flags.MUTABLE
-      val lhs = new ListBuffer[{Int, Name}]
+      val lhs = new ListBuffer[Pair[Int, Name]]
       do {
-        lhs += {in.skipToken(), ident()}
+        lhs += Pair(in.skipToken(), ident())
       } while (in.token == COMMA)
       val tp = typedOpt()
       val rhs = if (tp.isEmpty || in.token == EQUALS) {
@@ -1840,7 +1742,7 @@ trait Parsers requires SyntaxAnalyzer {
         newmods = newmods | Flags.DEFERRED
         EmptyTree
       }
-      for (val {pos, name} <- lhs.toList) yield
+      for (val Pair(pos, name) <- lhs.toList) yield
         atPos(pos) { ValDef(newmods, name, tp.duplicate, rhs.duplicate) }
     }
 
@@ -1963,10 +1865,10 @@ trait Parsers requires SyntaxAnalyzer {
         implicitClassViews = implicitViewBuf.toList
         //if (mods.hasFlag(Flags.CASE) && in.token != LPAREN) accept(LPAREN)
         val constrAnnots = annotations()
-        val {constrMods, vparamss} =
-          if (mods.hasFlag(Flags.TRAIT)) {NoMods, List()}
-          else {accessModifierOpt(),
-                paramClauses(name, implicitClassViews, mods.hasFlag(Flags.CASE))}
+        val Pair(constrMods, vparamss) =
+          if (mods.hasFlag(Flags.TRAIT)) Pair(NoMods, List())
+          else Pair(accessModifierOpt(),
+                    paramClauses(name, implicitClassViews, mods.hasFlag(Flags.CASE)))
         val thistpe = requiresTypeOpt()
         val template = classTemplate(mods, name, constrMods withAnnotations constrAnnots, vparamss)
         val mods1 = if (mods.hasFlag(Flags.TRAIT) &&
@@ -2162,7 +2064,7 @@ trait Parsers requires SyntaxAnalyzer {
       if (settings.Xplugtypes.value) {
         while(in.token == LBRACKET) {
           accept(LBRACKET)
-          exps ++= argExprs
+          exps ++= exprs()
           accept(RBRACKET)
         }
       }
@@ -2177,7 +2079,7 @@ trait Parsers requires SyntaxAnalyzer {
         var pos = in.currentPos
         val aname = atPos(pos) { Ident(ident()) }
         accept(EQUALS)
-        atPos(pos) { Assign(aname, liftingScope(prefixExpr())) }
+        atPos(pos) { Assign(aname, stripParens(prefixExpr())) }
       }
       val pos = in.currentPos
       var t: Tree = convertToTypeId(stableId())
@@ -2222,11 +2124,8 @@ trait Parsers requires SyntaxAnalyzer {
      *                 | LocalModifiers TmplDef
      *                 | Expr1
      *                 |
-     *  Tuple        ::= [Expr1 `,' {Expr1 `,'} [Expr1]]
      */
-    def blockStatSeq(stats: ListBuffer[Tree]): List[Tree] =
-      blockStatSeqOrTuple(false, stats)
-    def blockStatSeqOrTuple(tupleOK: boolean, stats: ListBuffer[Tree]): List[Tree] = {
+    def blockStatSeq(stats: ListBuffer[Tree]): List[Tree] = {
       def localDef(mods: Modifiers) = {
         if (!(mods hasFlag ~Flags.IMPLICIT)) stats ++= defOrDcl(mods)
         else stats += tmplDef(mods)
@@ -2243,23 +2142,7 @@ trait Parsers requires SyntaxAnalyzer {
           stats ++= importClause()
           acceptStatSep()
         } else if (isExprIntro) {
-          val expr = blockStatExpr()
-          if (in.token == COMMA) {
-            val exprbuf = new ListBuffer[Tree] + expr
-            while (in.token == COMMA) {
-              in.nextToken()
-              if (in.token != RBRACE) exprbuf += expr1()
-            }
-            val exprs = exprbuf.toList
-            if (in.token == ARROW) {
-              val vdefs = exprs flatMap convertToParams
-              checkSize("function arguments", vdefs.length, definitions.MaxFunctionArity)
-              stats += atPos(in.skipToken()) { Function(vdefs, block()) }
-            } else {
-              checkSize("tuple elements:", exprs.length, definitions.MaxTupleArity)
-              stats += makeTupleTerm(exprs, false)
-            }
-          } else stats += expr
+          stats += blockStatExpr()
           if (in.token != RBRACE && in.token != CASE) acceptStatSep()
         } else if (isDefIntro) {
           localDef(NoMods)
diff --git a/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala b/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
index e09b18dfd8..b197940207 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
@@ -57,16 +57,16 @@ abstract class TreeBuilder {
 
   /** Traverse pattern and collect all variable names with their types in buffer */
   private object getvarTraverser extends Traverser {
-    val buf = new ListBuffer[{Name, Tree}]
+    val buf = new ListBuffer[Pair[Name, Tree]]
     def init: Traverser = { buf.clear; this }
     override def traverse(tree: Tree): unit = tree match {
       case Bind(name, Typed(tree1, tpt)) =>
         if ((name != nme.WILDCARD) && (buf.elements forall (name !=)))
-          buf += {name, tpt}
+          buf += Pair(name, tpt)
         traverse(tree1)
       case Bind(name, tree1) =>
         if ((name != nme.WILDCARD) && (buf.elements forall (name !=)))
-          buf += {name, TypeTree()}
+          buf += Pair(name, TypeTree())
         traverse(tree1)
       case _ =>
         super.traverse(tree)
@@ -76,7 +76,7 @@ abstract class TreeBuilder {
   /** Returns list of all pattern variables, possibly with their types,
    *  without duplicates
    */
-  private def getVariables(tree: Tree): List[{Name, Tree}] = {
+  private def getVariables(tree: Tree): List[Pair[Name, Tree]] = {
     getvarTraverser.init.traverse(tree)
     getvarTraverser.buf.toList
   }
@@ -92,48 +92,48 @@ abstract class TreeBuilder {
     case _ => makeTuple(trees, false)
   }
 
-  def makeTuplePattern(trees: List[Tree]): Tree = trees match {
-    case List() => Literal(())
-    case _ => makeTuple(trees, false)
-  }
-
   def makeTupleType(trees: List[Tree], flattenUnary: boolean): Tree = trees match {
     case List() => scalaUnitConstr
     case List(tree) if flattenUnary => tree
     case _ => AppliedTypeTree(scalaDot(newTypeName("Tuple" + trees.length)), trees)
   }
 
+  def stripParens(t: Tree) = t match {
+    case Parens(ts) => atPos(t.pos) { makeTupleTerm(ts, true) }
+    case _ => t
+  }
+
   def makeAnnotated(t: Tree, attr: Tree): Tree = attr match {
     case Annotation(constr, elements) => Annotated(constr, elements, t) setPos attr.pos
   }
 
   /** If tree is a variable pattern, return Some("its name and type").
    *  Otherwise return none */
-  private def matchVarPattern(tree: Tree): Option[{Name, Tree}] = tree match {
-    case Ident(name) => Some{name, TypeTree()}
-    case Bind(name, Ident(nme.WILDCARD)) => Some{name, TypeTree()}
-    case Typed(Ident(name), tpt) => Some{name, tpt}
-    case Bind(name, Typed(Ident(nme.WILDCARD), tpt)) => Some{name, tpt}
+  private def matchVarPattern(tree: Tree): Option[Pair[Name, Tree]] = tree match {
+    case Ident(name) => Some(Pair(name, TypeTree()))
+    case Bind(name, Ident(nme.WILDCARD)) => Some(Pair(name, TypeTree()))
+    case Typed(Ident(name), tpt) => Some(Pair(name, tpt))
+    case Bind(name, Typed(Ident(nme.WILDCARD), tpt)) => Some(Pair(name, tpt))
     case _ => None
   }
 
   /** Create tree representing (unencoded) binary operation expression or pattern. */
   def makeBinop(isExpr: boolean, left: Tree, op: Name, right: Tree): Tree = {
     val arguments = right match {
-      case ArgumentExprs(args) => args
+      case Parens(args) => args
       case _ => List(right)
     }
     if (isExpr) {
       if (treeInfo.isLeftAssoc(op)) {
-        Apply(Select(left, op.encode), arguments)
+        Apply(Select(stripParens(left), op.encode), arguments)
       } else {
         val x = freshName();
         Block(
-          List(ValDef(Modifiers(SYNTHETIC), x, TypeTree(), left)),
-          Apply(Select(right, op.encode), List(Ident(x))))
+          List(ValDef(Modifiers(SYNTHETIC), x, TypeTree(), stripParens(left))),
+          Apply(Select(stripParens(right), op.encode), List(Ident(x))))
       }
     } else {
-      Apply(Ident(op.encode), left :: arguments)
+      Apply(Ident(op.encode), stripParens(left) :: arguments)
     }
   }
 
@@ -259,7 +259,7 @@ abstract class TreeBuilder {
   private def makeFor(mapName: Name, flatMapName: Name, enums: List[Enumerator], body: Tree): Tree = {
 
     def makeClosure(pat: Tree, body: Tree): Tree = matchVarPattern(pat) match {
-      case Some{name, tpt} =>
+      case Some(Pair(name, tpt)) =>
         Function(List(ValDef(Modifiers(PARAM), name, tpt, EmptyTree)), body)
       case None =>
         makeVisitor(List(CaseDef(pat, EmptyTree, body)), false)
@@ -385,7 +385,7 @@ abstract class TreeBuilder {
 
   /** Create tree for pattern definition &lt;mods val pat0 = rhs&gt; */
   def makePatDef(mods: Modifiers, pat: Tree, rhs: Tree): List[Tree] = matchVarPattern(pat) match {
-    case Some{name, tpt} =>
+    case Some(Pair(name, tpt)) =>
       List(ValDef(mods, name, tpt, rhs))
 
     case None =>
@@ -410,13 +410,13 @@ abstract class TreeBuilder {
       vars match {
         case List() =>
           List(matchExpr)
-        case List{vname, tpt} =>
+        case List(Pair(vname, tpt)) =>
           List(ValDef(mods, vname, tpt, matchExpr))
         case _ =>
           val tmp = freshName()
           val firstDef = ValDef(Modifiers(PRIVATE | LOCAL | SYNTHETIC), tmp, TypeTree(), matchExpr)
           var cnt = 0
-          val restDefs = for (val {vname, tpt} <- vars) yield {
+          val restDefs = for (val Pair(vname, tpt) <- vars) yield {
             cnt = cnt + 1
             ValDef(mods, vname, tpt, Select(Ident(tmp), newTermName("_" + cnt)))
           }
@@ -448,5 +448,5 @@ abstract class TreeBuilder {
       makePackaging(qual, List(PackageDef(name, stats)))
   }
 
-  case class ArgumentExprs(args: List[Tree]) extends Tree
+  case class Parens(args: List[Tree]) extends Tree
 }
diff --git a/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala b/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
index 2622be079a..0219442b8a 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/GenICode.scala
@@ -484,34 +484,34 @@ abstract class GenICode extends SubComponent  {
           val kind = toTypeKind(tree.tpe)
           var handlers = for (val CaseDef(pat, _, body) <- catches.reverse)
             yield pat match {
-              case Typed(Ident(nme.WILDCARD), tpt) => {tpt.tpe.symbol, kind, {
+              case Typed(Ident(nme.WILDCARD), tpt) => Triple(tpt.tpe.symbol, kind, {
                 ctx: Context =>
                   ctx.bb.emit(DROP(REFERENCE(tpt.tpe.symbol)));
                   val ctx1 = genLoad(body, ctx, kind);
                   genLoad(finalizer, ctx1, UNIT);
-                }}
+                })
 
-              case Ident(nme.WILDCARD) => {definitions.ThrowableClass, kind, {
+              case Ident(nme.WILDCARD) => Triple(definitions.ThrowableClass, kind, {
                 ctx: Context =>
                   ctx.bb.emit(DROP(REFERENCE(definitions.ThrowableClass)))
                   val ctx1 = genLoad(body, ctx, kind)
                   genLoad(finalizer, ctx1, UNIT)
-                }}
+                })
 
               case Bind(name, _) =>
                 val exception = new Local(pat.symbol, toTypeKind(pat.symbol.tpe), false)
                 ctx.method.addLocal(exception);
 
-                {pat.symbol.tpe.symbol, kind, {
+                Triple(pat.symbol.tpe.symbol, kind, {
                   ctx: Context =>
                     ctx.bb.emit(STORE_LOCAL(exception), pat.pos);
                   val ctx1 = genLoad(body, ctx, kind);
                   genLoad(finalizer, ctx1, UNIT);
-                }}
+                })
             }
 
           if (finalizer != EmptyTree)
-            handlers = { NoSymbol, kind, {
+            handlers = Triple(NoSymbol, kind, {
               ctx: Context =>
                 val exception = new Local(ctx.method.symbol
                                           .newVariable(finalizer.pos, unit.fresh.newName("exc"))
@@ -525,7 +525,7 @@ abstract class GenICode extends SubComponent  {
               ctx1.bb.emit(THROW());
               ctx1.bb.enterIgnoreMode;
               ctx1
-            }} :: handlers;
+            }) :: handlers;
 
           ctx.Try(
             bodyCtx => {
@@ -1273,9 +1273,9 @@ abstract class GenICode extends SubComponent  {
       def genComparisonOp(l: Tree, r: Tree, code: Int): Unit = {
         // special-case reference (in)equality test for null
         if (code == scalaPrimitives.ID || code == scalaPrimitives.NI) {
-          val expr: Tree = {l, r} match {
-            case {Literal(Constant(null)), expr} => expr
-            case {expr, Literal(Constant(null))} => expr
+          val expr: Tree = Pair(l, r) match {
+            case Pair(Literal(Constant(null)), expr) => expr
+            case Pair(expr, Literal(Constant(null))) => expr
             case _ => null
           }
           if (expr ne null) {
@@ -1393,15 +1393,15 @@ abstract class GenICode extends SubComponent  {
           local
       }
 
-      {l, r} match {
+      Pair(l, r) match {
         // null == expr -> expr eq null
-        case {Literal(Constant(null)), expr} =>
+        case Pair(Literal(Constant(null)), expr) =>
           val ctx1 = genLoad(expr, ctx, ANY_REF_CLASS)
           ctx1.bb.emit(CZJUMP(thenCtx.bb, elseCtx.bb, EQ, ANY_REF_CLASS))
           ctx1.bb.close
 
         // expr == null -> if(expr eq null) true else expr.equals(null)
-        case {expr, Literal(Constant(null))} =>
+        case Pair(expr, Literal(Constant(null))) =>
           val eqEqTempLocal = getTempLocal
           var ctx1 = genLoad(expr, ctx, ANY_REF_CLASS)
           ctx1.bb.emit(DUP(ANY_REF_CLASS))
@@ -1808,7 +1808,7 @@ abstract class GenICode extends SubComponent  {
        *   } ))</code>
        */
       def Try(body: Context => Context,
-              handlers: List[{Symbol, TypeKind, (Context => Context)}],
+              handlers: List[Triple[Symbol, TypeKind, (Context => Context)]],
               finalizer: Tree) = {
         val outerCtx = this.dup
         val afterCtx = outerCtx.newBlock
diff --git a/src/compiler/scala/tools/nsc/backend/icode/Members.scala b/src/compiler/scala/tools/nsc/backend/icode/Members.scala
index 6116b73d1e..0f8d1091a1 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/Members.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/Members.scala
@@ -229,7 +229,7 @@ trait Members requires ICodes {
     var end: Int = _
 
     /** PC-based ranges for this local variable's visibility range */
-    var ranges: List[{Int, Int}] = Nil
+    var ranges: List[Pair[Int, Int]] = Nil
 
     override def equals(other: Any): Boolean = (
       other.isInstanceOf[Local] &&
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
index d412a4315e..0a4de0e814 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
@@ -203,7 +203,7 @@ abstract class GenJVM extends SubComponent {
     }
 
     def addExceptionsAttribute(sym: Symbol): Unit = {
-      val {excs, others} = sym.attributes.partition((a => a match {
+      val Pair(excs, others) = sym.attributes.partition((a => a match {
         case AttrInfo(ThrowsAttr, _, _) => true
         case _ => false
       }))
@@ -289,7 +289,7 @@ abstract class GenJVM extends SubComponent {
           buf.putShort(cpool.addUtf8("value").toShort)
           emitElement(consts.head)
         }
-        for (val {name, value} <- nvPairs) {
+        for (val Pair(name, value) <- nvPairs) {
           buf.putShort(cpool.addUtf8(name.toString()).toShort)
           emitElement(value)
         }
@@ -593,7 +593,7 @@ abstract class GenJVM extends SubComponent {
           if (! (covered contains b) ) {
             if (start >= 0) { // we're inside a handler range
               end = labels(b).getAnchor()
-              ranges = {start, end} :: ranges
+              ranges = Pair(start, end) :: ranges
               start = -1
             }
           } else {
@@ -612,7 +612,7 @@ abstract class GenJVM extends SubComponent {
          * code!
          */
         if (start >= 0) {
-          ranges = {start, jcode.getPC()} :: ranges;
+          ranges = Pair(start, jcode.getPC()) :: ranges;
         }
 
         if (covered != Nil)
@@ -989,10 +989,10 @@ abstract class GenJVM extends SubComponent {
 
           case SCOPE_EXIT(lv) =>
             if (varsInBlock contains lv) {
-              lv.ranges = {lv.start, jcode.getPC()} :: lv.ranges
+              lv.ranges = Pair(lv.start, jcode.getPC()) :: lv.ranges
               varsInBlock -= lv
             } else if (b.varsInScope contains lv) {
-              lv.ranges = {labels(b).getAnchor(), jcode.getPC()} :: lv.ranges
+              lv.ranges = Pair(labels(b).getAnchor(), jcode.getPC()) :: lv.ranges
               b.varsInScope -= lv
             } else
               assert(false, "Illegal local var nesting: " + method)
@@ -1022,10 +1022,10 @@ abstract class GenJVM extends SubComponent {
 
       // local vars that survived this basic block
       for (val lv <- varsInBlock) {
-        lv.ranges = {lv.start, jcode.getPC()} :: lv.ranges
+        lv.ranges = Pair(lv.start, jcode.getPC()) :: lv.ranges
       }
       for (val lv <- b.varsInScope) {
-        lv.ranges = {labels(b).getAnchor(), jcode.getPC()} :: lv.ranges
+        lv.ranges = Pair(labels(b).getAnchor(), jcode.getPC()) :: lv.ranges
       }
     }
 
@@ -1101,67 +1101,67 @@ abstract class GenJVM extends SubComponent {
               abort("Unknown arithmetic primitive " + primitive)
           }
 
-        case Logical(op, kind) => {op, kind} match {
-          case {AND, LONG} =>
+        case Logical(op, kind) => Pair(op, kind) match {
+          case Pair(AND, LONG) =>
             jcode.emitLAND()
-          case {AND, INT} =>
+          case Pair(AND, INT) =>
             jcode.emitIAND()
-          case {AND, _} =>
+          case Pair(AND, _) =>
             jcode.emitIAND()
             if (kind != BOOL)
               jcode.emitT2T(javaType(INT), javaType(kind));
 
-          case {OR, LONG} =>
+          case Pair(OR, LONG) =>
             jcode.emitLOR()
-          case {OR, INT} =>
+          case Pair(OR, INT) =>
             jcode.emitIOR()
-          case {OR, _} =>
+          case Pair(OR, _) =>
             jcode.emitIOR()
             if (kind != BOOL)
               jcode.emitT2T(javaType(INT), javaType(kind));
 
-          case {XOR, LONG} =>
+          case Pair(XOR, LONG) =>
             jcode.emitLXOR()
-          case {XOR, INT} =>
+          case Pair(XOR, INT) =>
             jcode.emitIXOR()
-          case {XOR, _} =>
+          case Pair(XOR, _) =>
             jcode.emitIXOR()
             if (kind != BOOL)
               jcode.emitT2T(javaType(INT), javaType(kind));
         }
 
-        case Shift(op, kind) => {op, kind} match {
-          case {LSL, LONG} =>
+        case Shift(op, kind) => Pair(op, kind) match {
+          case Pair(LSL, LONG) =>
             jcode.emitLSHL()
-          case {LSL, INT} =>
+          case Pair(LSL, INT) =>
             jcode.emitISHL()
-          case {LSL, _} =>
+          case Pair(LSL, _) =>
             jcode.emitISHL()
             jcode.emitT2T(javaType(INT), javaType(kind))
 
-          case {ASR, LONG} =>
+          case Pair(ASR, LONG) =>
             jcode.emitLSHR()
-          case {ASR, INT} =>
+          case Pair(ASR, INT) =>
             jcode.emitISHR()
-          case {ASR, _} =>
+          case Pair(ASR, _) =>
             jcode.emitISHR()
             jcode.emitT2T(javaType(INT), javaType(kind))
 
-          case {LSR, LONG} =>
+          case Pair(LSR, LONG) =>
             jcode.emitLUSHR()
-          case {LSR, INT} =>
+          case Pair(LSR, INT) =>
             jcode.emitIUSHR()
-          case {LSR, _} =>
+          case Pair(LSR, _) =>
             jcode.emitIUSHR()
             jcode.emitT2T(javaType(INT), javaType(kind))
         }
 
-        case Comparison(op, kind) => {op, kind} match {
-          case {CMP, LONG}    => jcode.emitLCMP()
-          case {CMPL, FLOAT}  => jcode.emitFCMPL()
-          case {CMPG, FLOAT}  => jcode.emitFCMPG()
-          case {CMPL, DOUBLE} => jcode.emitDCMPL()
-          case {CMPG, DOUBLE} => jcode.emitDCMPL()
+        case Comparison(op, kind) => Pair(op, kind) match {
+          case Pair(CMP, LONG)    => jcode.emitLCMP()
+          case Pair(CMPL, FLOAT)  => jcode.emitFCMPL()
+          case Pair(CMPG, FLOAT)  => jcode.emitFCMPG()
+          case Pair(CMPL, DOUBLE) => jcode.emitDCMPL()
+          case Pair(CMPG, DOUBLE) => jcode.emitDCMPL()
         }
 
         case Conversion(src, dst) =>
@@ -1449,7 +1449,7 @@ abstract class GenJVM extends SubComponent {
 
             val index = indexOf(lv).asInstanceOf[Short]
             val tpe   = javaType(lv.kind).getSignature()
-            for (val {start, end} <- lv.ranges) {
+            for (val Pair(start, end) <- lv.ranges) {
               emitEntry(name, tpe, index, start.asInstanceOf[Short], (end - start).asInstanceOf[Short])
             }
         }
@@ -1463,10 +1463,10 @@ abstract class GenJVM extends SubComponent {
 
 
     /** Merge adjacent ranges. */
-    private def mergeEntries(ranges: List[{Int, Int}]): List[{Int, Int}] =
-      (ranges.foldLeft(Nil: List[{Int, Int}]) { (collapsed: List[{Int, Int}], p: {Int, Int}) => {collapsed, p} match {
-        case { Nil, _ } => List(p)
-        case { {s1, e1} :: rest, {s2, e2} } if (e1 == s2) => {s1, e2} :: rest
+    private def mergeEntries(ranges: List[Pair[Int, Int]]): List[Pair[Int, Int]] =
+      (ranges.foldLeft(Nil: List[Pair[Int, Int]]) { (collapsed: List[Pair[Int, Int]], p: Pair[Int, Int]) => Pair(collapsed, p) match {
+        case Pair(Nil, _) => List(p)
+        case Pair(Pair(s1, e1) :: rest, Pair(s2, e2)) if (e1 == s2) => Pair(s1, e2) :: rest
         case _ => p :: collapsed
       }}).reverse
 
diff --git a/src/compiler/scala/tools/nsc/backend/msil/GenMSIL.scala b/src/compiler/scala/tools/nsc/backend/msil/GenMSIL.scala
index 2d16388b37..3623d125ea 100644
--- a/src/compiler/scala/tools/nsc/backend/msil/GenMSIL.scala
+++ b/src/compiler/scala/tools/nsc/backend/msil/GenMSIL.scala
@@ -889,7 +889,7 @@ abstract class GenMSIL extends SubComponent {
 	      def leavingBlocks(blocks: List[BasicBlock]): List[Pair[BasicBlock, List[BasicBlock]]] = {
 		for {val b <- blocks
 		     val t = outsideTargets(b, blocks)
-		     t.length != 0 } yield {b, t}
+		     t.length != 0 } yield Pair(b, t)
 	      }
 
 	      def replaceOutJumps(blocks: List[BasicBlock], leaving: List[Pair[BasicBlock, List[BasicBlock]]], exh: ExceptionHandler):Pair[List[BasicBlock], Option[BasicBlock]] = {
@@ -926,12 +926,12 @@ abstract class GenMSIL extends SubComponent {
 		  val target = p._2(0) // the elemets of p._2 are all the same, checked before
 		  replaceJump(lBlock, target, jumpOutBlock)
 		})
-		{blocks ::: List(jumpOutBlock), Some(jumpOutBlock)}
+		Pair(blocks ::: List(jumpOutBlock), Some(jumpOutBlock))
 	      }
 
 	      val leaving = leavingBlocks(blocks)
 	      if (leaving.length == 0)
-		{blocks, None}
+		Pair(blocks, None)
 	      else if (leaving.length == 1) {
 		val outside = leaving(0)._2
 		assert(outside.forall(b => b == outside(0)), "exception-block leaving to multiple targets")
@@ -940,7 +940,7 @@ abstract class GenMSIL extends SubComponent {
 		else
 		  assert(firstBlockAfter(exh) == outside(0), "try/catch leaving to multiple targets: " + firstBlockAfter(exh) + ", new: " + outside(0))
 		val last = leaving(0)._1
-		{blocks.diff(List(last)) ::: List(last), None}
+		Pair(blocks.diff(List(last)) ::: List(last), None)
 	      } else {
 		val outside = leaving.flatMap(p => p._2)
 		assert(outside.forall(b => b == outside(0)), "exception-block leaving to multiple targets")
@@ -968,7 +968,7 @@ abstract class GenMSIL extends SubComponent {
 	    var singleAffectedHandler: ExceptionHandler = affectedHandlers(0) // List[ExceptionHandler] = Nil
 	    var exceptionBlock: Option[ExceptionBlock] = None
 	    affectedHandlers.foreach(h1 => {
-	      val {adaptedBlocks, newBlock} = adaptBlocks(blocksToPut.intersect(h1.blocks), singleAffectedHandler)
+	      val Pair(adaptedBlocks, newBlock) = adaptBlocks(blocksToPut.intersect(h1.blocks), singleAffectedHandler)
 	      newBlock match {
 		case Some(block) =>
 		  blocksToPut = blocksToPut ::: List(block)
@@ -986,7 +986,7 @@ abstract class GenMSIL extends SubComponent {
 		  val excBlock = currentBlock.addExceptionBlock(singleAffectedHandler)
 		  exceptionBlock = Some(excBlock)
 
-		  val {tryBlocks, newBlock} = adaptBlocks(blocksToPut.intersect(singleAffectedHandler.covered), singleAffectedHandler)
+		  val Pair(tryBlocks, newBlock) = adaptBlocks(blocksToPut.intersect(singleAffectedHandler.covered), singleAffectedHandler)
 
 		  newBlock match {
 		    case Some(block) =>
@@ -998,7 +998,7 @@ abstract class GenMSIL extends SubComponent {
 		  addBlocks(tryBlocks)
 
 		  if (singleAffectedHandler.finalizer != null && singleAffectedHandler.finalizer != NoFinalizer) {
-		    val {blocks0, newBlock} = adaptBlocks(blocksToPut.intersect(singleAffectedHandler.finalizer.blocks), singleAffectedHandler)
+		    val Pair(blocks0, newBlock) = adaptBlocks(blocksToPut.intersect(singleAffectedHandler.finalizer.blocks), singleAffectedHandler)
 		    newBlock match {
 		      case Some(block) =>
 			blocksToPut = blocksToPut ::: List(block)
@@ -1379,13 +1379,13 @@ abstract class GenMSIL extends SubComponent {
               }
 
 	      // method: implicit view(FunctionX[PType0, PType1, ...,PTypeN, ResType]):DelegateType
-	      val {isDelegateView, paramType, resType} = atPhase(currentRun.typerPhase){
+	      val Triple(isDelegateView, paramType, resType) = atPhase(currentRun.typerPhase){
 		msym.tpe match {
 		  case MethodType(parameterTypes, resultType)
 		  if (parameterTypes.length == 1 && msym.name == nme.view_) =>
 		    val isDel = definitions.isCorrespondingDelegate(resultType, parameterTypes(0))
-		    {isDel, parameterTypes(0), resultType}
-		  case _ => {false, null, null}
+		    Triple(isDel, parameterTypes(0), resultType)
+		  case _ => Triple(false, null, null)
 		}
 	      }
 	      if (doEmit && isDelegateView) {
@@ -2206,8 +2206,8 @@ abstract class GenMSIL extends SubComponent {
 
 
       // create the static caller method and the delegate object
-      val {paramTypes, returnType} = delegateType.member(nme.apply).tpe match {
-	case MethodType(delParams, delReturn) => {delParams, delReturn}
+      val Pair(paramTypes, returnType) = delegateType.member(nme.apply).tpe match {
+	case MethodType(delParams, delReturn) => Pair(delParams, delReturn)
 	case _ => abort("not a delegate type: "  + delegateType)
       }
       val caller: MethodBuilder = delegateCallers.DefineMethod(
diff --git a/src/compiler/scala/tools/nsc/matching/PatternMatchers.scala b/src/compiler/scala/tools/nsc/matching/PatternMatchers.scala
index c66c3e1ff8..75ab5623fd 100644
--- a/src/compiler/scala/tools/nsc/matching/PatternMatchers.scala
+++ b/src/compiler/scala/tools/nsc/matching/PatternMatchers.scala
@@ -1044,7 +1044,7 @@ print()
       //Console.println("sel:"+selector+" last"+lastSelector+" - "+(selector == lastSelector))
         val next = _h.next;
         //res = And(mkNegate(res), toTree(node.or, selector));
-        val {doOptimize, coveredCases, remainingCases} = _h.optimize1()
+        val Triple(doOptimize, coveredCases, remainingCases) = _h.optimize1()
         if(!remainingCases.isEmpty && doCheckExhaustive) {
           carryCovered = carryCovered ++ coveredCases // ??
           if(next != null && next.or.and.isUnguardedBody) {
@@ -1301,7 +1301,7 @@ print()
                 true
               case _ =>
                 if(settings.XprintOuterMatches.value)
-                  cunit.warning(node.pos, "can't be sure statically that these outers are equal:"+{left,right}.toString)
+                  cunit.warning(node.pos, "can't be sure statically that these outers are equal:"+Pair(left,right).toString)
                 false
             }
 
diff --git a/src/compiler/scala/tools/nsc/matching/PatternNodes.scala b/src/compiler/scala/tools/nsc/matching/PatternNodes.scala
index cd0d5da3d8..b436dccefb 100644
--- a/src/compiler/scala/tools/nsc/matching/PatternNodes.scala
+++ b/src/compiler/scala/tools/nsc/matching/PatternNodes.scala
@@ -327,16 +327,16 @@ trait PatternNodes requires transform.ExplicitOuter {
     /** returns true if this tree is optimizable
      *  throws a warning if is not exhaustive
      */
-    def optimize1(): { Boolean, SymSet, SymSet } = {
+    def optimize1(): Triple[Boolean, SymSet, SymSet] = {
       import symtab.Flags
 
       val selType = this.getTpe
 
       if (!isSubType(selType, definitions.ScalaObjectClass.tpe))
-        return {false, null, emptySymbolSet};
+        return Triple(false, null, emptySymbolSet)
 
       if(this.or eq null)
-        return {false, null, emptySymbolSet}  // only case _
+        return Triple(false, null, emptySymbolSet)  // only case _
 
       def checkExCoverage(tpesym:Symbol): SymSet =
         if(!tpesym.hasFlag(Flags.SEALED)) emptySymbolSet
@@ -409,7 +409,7 @@ trait PatternNodes requires transform.ExplicitOuter {
       }
 
       this.forEachBranch(traverse)
-      return {res && (cases > 2), coveredCases, remainingCases};
+      return Triple(res && (cases > 2), coveredCases, remainingCases)
     } // def optimize
 
   }
diff --git a/src/compiler/scala/tools/nsc/symtab/SymbolLoaders.scala b/src/compiler/scala/tools/nsc/symtab/SymbolLoaders.scala
index 178c6155fa..8fe03975f3 100644
--- a/src/compiler/scala/tools/nsc/symtab/SymbolLoaders.scala
+++ b/src/compiler/scala/tools/nsc/symtab/SymbolLoaders.scala
@@ -174,7 +174,7 @@ abstract class SymbolLoaders {
       }
 
       // do classes first
-      for (val {name, file} <- classes.elements) {
+      for (val Pair(name, file) <- classes.elements) {
         val loader = if (!file.isSourceFile) {
           new ClassfileLoader(file.classFile, file.sourceFile, file.sourcePath)
         } else {
@@ -184,7 +184,7 @@ abstract class SymbolLoaders {
         enterClassAndModule(name, loader)
       }
 
-      for (val {name, file} <- packages.elements)
+      for (val Pair(name, file) <- packages.elements)
         enterPackage(name, newPackageLoader(file))
     }
   }
diff --git a/src/compiler/scala/tools/nsc/symtab/Symbols.scala b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
index fad85cfc4a..2db48eaa41 100644
--- a/src/compiler/scala/tools/nsc/symtab/Symbols.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
@@ -1306,7 +1306,7 @@ trait Symbols requires SymbolTable {
     def cloneSymbolImpl(owner: Symbol): Symbol = throw new Error()
   }
 
-  case class AttrInfo(atp: Type, args: List[Constant], assocs: List[{Name, Constant}]) {
+  case class AttrInfo(atp: Type, args: List[Constant], assocs: List[Pair[Name, Constant]]) {
     override def toString: String =
       atp +
       (if (args.isEmpty) "" else args.mkString("(", ", ", ")")) +
diff --git a/src/compiler/scala/tools/nsc/symtab/Types.scala b/src/compiler/scala/tools/nsc/symtab/Types.scala
index 348f9c2f77..27bc11ff67 100644
--- a/src/compiler/scala/tools/nsc/symtab/Types.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Types.scala
@@ -918,7 +918,7 @@ trait Types requires SymbolTable {
           def apply(tp: Type): Type = {
             tp match {
               case TypeRef(_, sym, args) =>
-                for (val {tparam1, arg} <- sym.info.typeParams zip args)
+                for (val Pair(tparam1, arg) <- sym.info.typeParams zip args)
                   if (arg contains tparam) {
                     addRef(NonExpansive, tparam, tparam1)
                     if (arg.symbol != tparam) addRef(Expansive, tparam, tparam1)
@@ -943,7 +943,7 @@ trait Types requires SymbolTable {
       val lastRefs = Array(refs(0), refs(1))
       state = Initialized
       var change = false
-      for (val {from, targets} <- refs(NonExpansive).elements)
+      for (val Pair(from, targets) <- refs(NonExpansive).elements)
         for (val target <- targets) {
           var thatInfo = classInfo(target)
           if (thatInfo.state != Initialized)
@@ -951,7 +951,7 @@ trait Types requires SymbolTable {
           addRefs(NonExpansive, from, thatInfo.getRefs(NonExpansive, target))
           addRefs(Expansive, from, thatInfo.getRefs(Expansive, target))
         }
-      for (val {from, targets} <- refs(Expansive).elements)
+      for (val Pair(from, targets) <- refs(Expansive).elements)
         for (val target <- targets) {
           var thatInfo = classInfo(target)
           addRefs(Expansive, from, thatInfo.getRefs(NonExpansive, target))
@@ -2012,40 +2012,40 @@ trait Types requires SymbolTable {
    *             equivalent types.
    */
   def isSameType(tp1: Type, tp2: Type): boolean = {
-    {tp1, tp2} match {
-      case {ErrorType, _} => true
-      case {WildcardType, _} => true
-      case {_, ErrorType} => true
-      case {_, WildcardType} => true
-
-      case {NoType, _} => false
-      case {NoPrefix, _} => tp2.symbol.isPackageClass
-      case {_, NoType} => false
-      case {_, NoPrefix} => tp1.symbol.isPackageClass
-
-      case {ThisType(sym1), ThisType(sym2)}
+    Pair(tp1, tp2) match {
+      case Pair(ErrorType, _) => true
+      case Pair(WildcardType, _) => true
+      case Pair(_, ErrorType) => true
+      case Pair(_, WildcardType) => true
+
+      case Pair(NoType, _) => false
+      case Pair(NoPrefix, _) => tp2.symbol.isPackageClass
+      case Pair(_, NoType) => false
+      case Pair(_, NoPrefix) => tp1.symbol.isPackageClass
+
+      case Pair(ThisType(sym1), ThisType(sym2))
       if (sym1 == sym2) =>
         true
-      case {SingleType(pre1, sym1), SingleType(pre2, sym2)}
+      case Pair(SingleType(pre1, sym1), SingleType(pre2, sym2))
       if ((sym1 == sym2) && (pre1 =:= pre2)) =>
         true
 /*
-      case {SingleType(pre1, sym1), ThisType(sym2)}
+      case Pair(SingleType(pre1, sym1), ThisType(sym2))
       if (sym1.isModule &&
           sym1.moduleClass == sym2 &&
           pre1 =:= sym2.owner.thisType) =>
         true
-      case {ThisType(sym1), SingleType(pre2, sym2)}
+      case Pair(ThisType(sym1), SingleType(pre2, sym2))
       if (sym2.isModule &&
           sym2.moduleClass == sym1 &&
           pre2 =:= sym1.owner.thisType) =>
         true
 */
-      case {ConstantType(value1), ConstantType(value2)} =>
+      case Pair(ConstantType(value1), ConstantType(value2)) =>
         value1 == value2
-      case {TypeRef(pre1, sym1, args1), TypeRef(pre2, sym2, args2)} =>
+      case Pair(TypeRef(pre1, sym1, args1), TypeRef(pre2, sym2, args2)) =>
         sym1 == sym2 && (phase.erasedTypes || pre1 =:= pre2) && isSameTypes(args1, args2)
-      case {RefinedType(parents1, ref1), RefinedType(parents2, ref2)} =>
+      case Pair(RefinedType(parents1, ref1), RefinedType(parents2, ref2)) =>
         def isSubScope(s1: Scope, s2: Scope): boolean = s2.toList.forall {
           sym2 =>
             val sym1 = s1.lookup(sym2.name)
@@ -2054,31 +2054,31 @@ trait Types requires SymbolTable {
         }
         //Console.println("is same? " + tp1 + " " + tp2 + " " + tp1.symbol.owner + " " + tp2.symbol.owner)//DEBUG
         isSameTypes(parents1, parents2) && isSubScope(ref1, ref2) && isSubScope(ref2, ref1)
-      case {MethodType(pts1, res1), MethodType(pts2, res2)} =>
+      case Pair(MethodType(pts1, res1), MethodType(pts2, res2)) =>
         (pts1.length == pts2.length &&
          isSameTypes(pts1, pts2) &&
          res1 =:= res2 &&
          tp1.isInstanceOf[ImplicitMethodType] == tp2.isInstanceOf[ImplicitMethodType])
-      case {PolyType(tparams1, res1), PolyType(tparams2, res2)} =>
+      case Pair(PolyType(tparams1, res1), PolyType(tparams2, res2)) =>
         (tparams1.length == tparams2.length &&
          List.forall2(tparams1, tparams2)
            ((p1, p2) => p1.info =:= p2.info.substSym(tparams2, tparams1)) &&
          res1 =:= res2.substSym(tparams2, tparams1))
-      case {TypeBounds(lo1, hi1), TypeBounds(lo2, hi2)} =>
+      case Pair(TypeBounds(lo1, hi1), TypeBounds(lo2, hi2)) =>
         lo1 =:= lo2 && hi1 =:= hi2
-      case {BoundedWildcardType(bounds), _} =>
+      case Pair(BoundedWildcardType(bounds), _) =>
         bounds containsType tp2
-      case {_, BoundedWildcardType(bounds)} =>
+      case Pair(_, BoundedWildcardType(bounds)) =>
         bounds containsType tp1
-      case {TypeVar(_, constr1), _} =>
+      case Pair(TypeVar(_, constr1), _) =>
         if (constr1.inst != NoType) constr1.inst =:= tp2
         else constr1 instantiate (wildcardToTypeVarMap(tp2))
-      case {_, TypeVar(_, constr2)} =>
+      case Pair(_, TypeVar(_, constr2)) =>
         if (constr2.inst != NoType) tp1 =:= constr2.inst
         else constr2 instantiate (wildcardToTypeVarMap(tp1))
-      case {AttributedType(_,atp), _} =>
+      case Pair(AttributedType(_,atp), _) =>
         isSameType(atp, tp2)
-      case {_, AttributedType(_,atp)} =>
+      case Pair(_, AttributedType(_,atp)) =>
         isSameType(tp1, atp)
       case _ =>
         if (tp1.isStable && tp2.isStable) {
@@ -2127,24 +2127,24 @@ trait Types requires SymbolTable {
    *  @return    ...
    */
   def isSubType0(tp1: Type, tp2: Type): boolean = {
-    {tp1, tp2} match {
-      case {ErrorType, _}    => true
-      case {WildcardType, _} => true
-      case {_, ErrorType}    => true
-      case {_, WildcardType} => true
-
-      case {NoType, _}   => false
-      case {NoPrefix, _} => tp2.symbol.isPackageClass
-      case {_, NoType}   => false
-      case {_, NoPrefix} => tp1.symbol.isPackageClass
-
-      case {ThisType(_), ThisType(_)}           => tp1 =:= tp2
-      case {ThisType(_), SingleType(_, _)}      => tp1 =:= tp2
-      case {SingleType(_, _), ThisType(_)}      => tp1 =:= tp2
-      case {SingleType(_, _), SingleType(_, _)} => tp1 =:= tp2
-      case {ConstantType(_), ConstantType(_)}   => tp1 =:= tp2
-
-      case {TypeRef(pre1, sym1, args1), TypeRef(pre2, sym2, args2)} =>
+    Pair(tp1, tp2) match {
+      case Pair(ErrorType, _)    => true
+      case Pair(WildcardType, _) => true
+      case Pair(_, ErrorType)    => true
+      case Pair(_, WildcardType) => true
+
+      case Pair(NoType, _)   => false
+      case Pair(NoPrefix, _) => tp2.symbol.isPackageClass
+      case Pair(_, NoType)   => false
+      case Pair(_, NoPrefix) => tp1.symbol.isPackageClass
+
+      case Pair(ThisType(_), ThisType(_))           => tp1 =:= tp2
+      case Pair(ThisType(_), SingleType(_, _))      => tp1 =:= tp2
+      case Pair(SingleType(_, _), ThisType(_))      => tp1 =:= tp2
+      case Pair(SingleType(_, _), SingleType(_, _)) => tp1 =:= tp2
+      case Pair(ConstantType(_), ConstantType(_))   => tp1 =:= tp2
+
+      case Pair(TypeRef(pre1, sym1, args1), TypeRef(pre2, sym2, args2)) =>
         //Console.println("isSubType " + tp1 + " " + tp2);//DEBUG
         def isSubArgs(tps1: List[Type], tps2: List[Type],
                       tparams: List[Symbol]): boolean = (
@@ -2172,50 +2172,50 @@ trait Types requires SymbolTable {
          ||
          // Console.println("last chance " + sym1 + " " + sym2 + " " + sym2.isClass + " " (sym2 isSubClass ObjectClass))
          sym1 == AllRefClass && sym2.isClass && sym2 != AllClass && (sym2 isSubClass ObjectClass))
-      case {MethodType(pts1, res1), MethodType(pts2, res2)} =>
+      case Pair(MethodType(pts1, res1), MethodType(pts2, res2)) =>
         (pts1.length == pts2.length &&
          matchingParams(pts1, pts2, tp2.isInstanceOf[JavaMethodType]) &&
          (res1 <:< res2) &&
          tp1.isInstanceOf[ImplicitMethodType] == tp2.isInstanceOf[ImplicitMethodType])
-      case {PolyType(tparams1, res1), PolyType(tparams2, res2)} =>
+      case Pair(PolyType(tparams1, res1), PolyType(tparams2, res2)) =>
         (tparams1.length == tparams2.length &&
          List.forall2(tparams1, tparams2)
            ((p1, p2) => p2.info.substSym(tparams2, tparams1) <:< p1.info) &&
          res1 <:< res2.substSym(tparams2, tparams1))
-      case {TypeBounds(lo1, hi1), TypeBounds(lo2, hi2)} =>
+      case Pair(TypeBounds(lo1, hi1), TypeBounds(lo2, hi2)) =>
         lo2 <:< lo1 && hi1 <:< hi2
-      case {BoundedWildcardType(bounds), _} =>
+      case Pair(BoundedWildcardType(bounds), _) =>
         bounds.lo <:< tp2
-      case {_, BoundedWildcardType(bounds)} =>
+      case Pair(_, BoundedWildcardType(bounds)) =>
         tp1 <:< bounds.hi
-      case {_, TypeVar(_, constr2)} =>
+      case Pair(_, TypeVar(_, constr2)) =>
         if (constr2.inst != NoType) tp1 <:< constr2.inst
         else { constr2.lobounds = tp1 :: constr2.lobounds; true }
-      case {TypeVar(_, constr1), _} =>
+      case Pair(TypeVar(_, constr1), _) =>
         if (constr1.inst != NoType) constr1.inst <:< tp2
         else { constr1.hibounds = tp2 :: constr1.hibounds; true }
-      case {AttributedType(_,atp1), _} =>
+      case Pair(AttributedType(_,atp1), _) =>
         atp1 <:< tp2
-      case {_, AttributedType(_,atp2)} =>
+      case Pair(_, AttributedType(_,atp2)) =>
         tp1 <:< atp2
-      case {_, TypeRef(pre2, sym2, args2)}
+      case Pair(_, TypeRef(pre2, sym2, args2))
       if sym2.isAbstractType && !(tp2 =:= tp2.bounds.lo) && (tp1 <:< tp2.bounds.lo) =>
         true
-      case {_, RefinedType(parents2, ref2)} =>
+      case Pair(_, RefinedType(parents2, ref2)) =>
         (parents2 forall tp1.<:<) && (ref2.toList forall tp1.specializes) &&
         (!parents2.exists(.symbol.isAbstractType) || tp1.symbol != AllRefClass)
-      case {RefinedType(parents1, ref1), _} =>
+      case Pair(RefinedType(parents1, ref1), _) =>
         parents1 exists (.<:<(tp2))
       /* todo: replace following with
-      case {ThisType(_), _}
+      case Pair(ThisType(_), _)
          | {SingleType(_, _), _}
          | {ConstantType(_), _} =>
          once patern matching bug is fixed */
-      case {ThisType(_), _} => tp1.singleDeref <:< tp2
-      case {SingleType(_, _), _} => tp1.singleDeref <:< tp2
-      case {ConstantType(_), _} => tp1.singleDeref <:< tp2
+      case Pair(ThisType(_), _) => tp1.singleDeref <:< tp2
+      case Pair(SingleType(_, _), _) => tp1.singleDeref <:< tp2
+      case Pair(ConstantType(_), _) => tp1.singleDeref <:< tp2
 
-      case {TypeRef(pre1, sym1, args1), _} =>
+      case Pair(TypeRef(pre1, sym1, args1), _) =>
         (sym1 == AllClass && tp2 <:< AnyClass.tpe
          ||
          sym1 == AllRefClass && tp2.isInstanceOf[SingletonType] && (tp1 <:< tp2.widen))
@@ -2260,21 +2260,21 @@ trait Types requires SymbolTable {
   }
 
   /** A function implementing <code>tp1</code> matches <code>tp2</code> */
-  private def matchesType(tp1: Type, tp2: Type): boolean = {tp1, tp2} match {
-    case {MethodType(pts1, res1), MethodType(pts2, res2)} =>
+  private def matchesType(tp1: Type, tp2: Type): boolean = Pair(tp1, tp2) match {
+    case Pair(MethodType(pts1, res1), MethodType(pts2, res2)) =>
       (matchingParams(pts1, pts2, tp2.isInstanceOf[JavaMethodType]) && (res1 matches res2) &&
        tp1.isInstanceOf[ImplicitMethodType] == tp2.isInstanceOf[ImplicitMethodType])
-    case {PolyType(tparams1, res1), PolyType(tparams2, res2)} =>
+    case Pair(PolyType(tparams1, res1), PolyType(tparams2, res2)) =>
       (tparams1.length == tparams2.length &&
        (res1 matches res2.substSym(tparams2, tparams1)))
-    case {PolyType(List(), rtp1), MethodType(List(), rtp2)} => matchesType(rtp1, rtp2)
-    case {MethodType(List(), rtp1), PolyType(List(), rtp2)} => matchesType(rtp1, rtp2)
-    case {PolyType(List(), rtp1), _} => matchesType(rtp1, tp2)
-    case {_, PolyType(List(), rtp2)} => matchesType(tp1, rtp2)
-    case {MethodType(_, _), _} => false
-    case {PolyType(_, _), _}   => false
-    case {_, MethodType(_, _)} => false
-    case {_, PolyType(_, _)}   => false
+    case Pair(PolyType(List(), rtp1), MethodType(List(), rtp2)) => matchesType(rtp1, rtp2)
+    case Pair(MethodType(List(), rtp1), PolyType(List(), rtp2)) => matchesType(rtp1, rtp2)
+    case Pair(PolyType(List(), rtp1), _) => matchesType(rtp1, tp2)
+    case Pair(_, PolyType(List(), rtp2)) => matchesType(tp1, rtp2)
+    case Pair(MethodType(_, _), _) => false
+    case Pair(PolyType(_, _), _)   => false
+    case Pair(_, MethodType(_, _)) => false
+    case Pair(_, PolyType(_, _))   => false
     case _ =>
       !phase.erasedTypes || tp1 =:= tp2
   }
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
index 8c0833e3bf..cf53db37a2 100644
--- a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
+++ b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
@@ -193,7 +193,7 @@ abstract class ClassfileParser {
             in.buf(start) != CONSTANT_METHODREF &&
             in.buf(start) != CONSTANT_INTFMETHODREF) errorBadTag(start)
         val ownerTpe = getClassOrArrayType(in.getChar(start + 1))
-        val {name, tpe} = getNameAndType(in.getChar(start + 3), ownerTpe)
+        val Pair(name, tpe) = getNameAndType(in.getChar(start + 3), ownerTpe)
         if (name == nme.MODULE_INSTANCE_FIELD) {
           val index = in.getChar(start + 1)
           val name = getExternalName(in.getChar(starts(index) + 1))
@@ -232,7 +232,7 @@ abstract class ClassfileParser {
               tpe = MethodType(formals, ownerTpe)
           }
 
-        p = {name, tpe}
+        p = Pair(name, tpe)
       }
       p
     }
@@ -700,7 +700,7 @@ abstract class ClassfileParser {
         val nvpairs = new ListBuffer[Pair[Name,Constant]]
         for (val i <- 0 until nargs) {
           val name = pool.getName(in.nextChar)
-          nvpairs += {name, parseTaggedConstant()}
+          nvpairs += Pair(name, parseTaggedConstant())
         }
         sym.attributes = AttrInfo(attrType, List(), nvpairs.toList) :: sym.attributes
       }
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/Pickler.scala b/src/compiler/scala/tools/nsc/symtab/classfile/Pickler.scala
index 68c504eb30..ebe7c6d763 100644
--- a/src/compiler/scala/tools/nsc/symtab/classfile/Pickler.scala
+++ b/src/compiler/scala/tools/nsc/symtab/classfile/Pickler.scala
@@ -169,15 +169,15 @@ abstract class Pickler extends SubComponent {
       }
 
     private def putChildren(sym: Symbol, children: Set[Symbol]): unit = {
-      assert(putEntry{sym, children})
+      assert(putEntry(Pair(sym, children)))
       children foreach putSymbol
     }
 
     private def putAnnotation(sym: Symbol, attr: AttrInfo): unit = {
-      assert(putEntry{sym, attr})
+      assert(putEntry(Pair(sym, attr)))
       putType(attr.atp)
       for (val c <- attr.args) putConstant(c)
-      for (val {name, c} <- attr.assocs) { putEntry(name); putConstant(c) }
+      for (val Pair(name, c) <- attr.assocs) { putEntry(name); putConstant(c) }
     }
 
     // Phase 2 methods: Write all entries to byte array ------------------------------
@@ -279,13 +279,13 @@ abstract class Pickler extends SubComponent {
           LITERAL + c.tag
         case AttributedType(attribs, tp) =>
           writeBody(tp) // obviously, this should be improved
-        case {target: Symbol, attr @ AttrInfo(atp, args, assocs)} =>
+        case Pair(target: Symbol, attr @ AttrInfo(atp, args, assocs)) =>
           writeRef(target)
           writeRef(atp)
           for (val c <- args) writeRef(c)
-          for (val {name, c} <- assocs) { writeRef(name); writeRef(c) }
+          for (val Pair(name, c) <- assocs) { writeRef(name); writeRef(c) }
           ATTRIBUTE
-        case {target: Symbol, children: Set[_]} =>
+        case Pair(target: Symbol, children: Set[_]) =>
           writeRef(target)
           for (val c <- children) writeRef(c.asInstanceOf[Symbol])
           CHILDREN
diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/UnPickler.scala b/src/compiler/scala/tools/nsc/symtab/classfile/UnPickler.scala
index e28ed90b69..ac1d10e9be 100644
--- a/src/compiler/scala/tools/nsc/symtab/classfile/UnPickler.scala
+++ b/src/compiler/scala/tools/nsc/symtab/classfile/UnPickler.scala
@@ -288,10 +288,10 @@ abstract class UnPickler {
       if (tag == ATTRIBUTE) {
         val attrType = readTypeRef()
         val args = new ListBuffer[Constant]
-        val assocs = new ListBuffer[{Name, Constant}]
+        val assocs = new ListBuffer[Pair[Name, Constant]]
         while (readIndex != end) {
           val argref = readNat()
-          if (isNameEntry(argref)) assocs += {at(argref, readName), readConstantRef()}
+          if (isNameEntry(argref)) assocs += Pair(at(argref, readName), readConstantRef())
           else args += at(argref, readConstant)
         }
         val attr = AttrInfo(attrType, args.toList, assocs.toList)
diff --git a/src/compiler/scala/tools/nsc/typechecker/ConstantFolder.scala b/src/compiler/scala/tools/nsc/typechecker/ConstantFolder.scala
index 1610d237e0..7323b17fa3 100644
--- a/src/compiler/scala/tools/nsc/typechecker/ConstantFolder.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/ConstantFolder.scala
@@ -49,21 +49,21 @@ abstract class ConstantFolder {
                                            // compiler itself crashing
     }
 
-  private def foldUnop(op: Name, x: Constant): Constant = {op, x.tag} match {
-    case {nme.ZNOT, BooleanTag} => Constant(!x.booleanValue)
+  private def foldUnop(op: Name, x: Constant): Constant = Pair(op, x.tag) match {
+    case Pair(nme.ZNOT, BooleanTag) => Constant(!x.booleanValue)
 
-    case {nme.NOT , IntTag    } => Constant(~x.intValue)
-    case {nme.NOT , LongTag   } => Constant(~x.longValue)
+    case Pair(nme.NOT , IntTag    ) => Constant(~x.intValue)
+    case Pair(nme.NOT , LongTag   ) => Constant(~x.longValue)
 
-    case {nme.ADD , IntTag    } => Constant(+x.intValue)
-    case {nme.ADD , LongTag   } => Constant(+x.longValue)
-    case {nme.ADD , FloatTag  } => Constant(+x.floatValue)
-    case {nme.ADD , DoubleTag } => Constant(+x.doubleValue)
+    case Pair(nme.ADD , IntTag    ) => Constant(+x.intValue)
+    case Pair(nme.ADD , LongTag   ) => Constant(+x.longValue)
+    case Pair(nme.ADD , FloatTag  ) => Constant(+x.floatValue)
+    case Pair(nme.ADD , DoubleTag ) => Constant(+x.doubleValue)
 
-    case {nme.SUB , IntTag    } => Constant(-x.intValue)
-    case {nme.SUB , LongTag   } => Constant(-x.longValue)
-    case {nme.SUB , FloatTag  } => Constant(-x.floatValue)
-    case {nme.SUB , DoubleTag } => Constant(-x.doubleValue)
+    case Pair(nme.SUB , IntTag    ) => Constant(-x.intValue)
+    case Pair(nme.SUB , LongTag   ) => Constant(-x.longValue)
+    case Pair(nme.SUB , FloatTag  ) => Constant(-x.floatValue)
+    case Pair(nme.SUB , DoubleTag ) => Constant(-x.doubleValue)
 
     case _ => null
   }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
index 72f8d8540e..0fb3d02cc5 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
@@ -41,7 +41,7 @@ trait Contexts requires Analyzer {
       assert(pkg ne null)
       val qual = gen.mkAttributedStableRef(pkg)
       sc = sc.makeNewImport(
-        Import(qual, List({nme.WILDCARD, null}))
+        Import(qual, List(Pair(nme.WILDCARD, null)))
         .setSymbol(NoSymbol.newImport(NoPos).setFlag(SYNTHETIC).setInfo(ImportType(qual)))
         .setType(NoType))
       sc.depth = sc.depth + 1
@@ -364,12 +364,12 @@ trait Contexts requires Analyzer {
     }
 
     def pushTypeBounds(sym: Symbol): unit = {
-      savedTypeBounds = {sym, sym.info} :: savedTypeBounds
+      savedTypeBounds = Pair(sym, sym.info) :: savedTypeBounds
     }
 
     def restoreTypeBounds(tp: Type): Type = {
       var current = tp
-      for (val {sym, info} <- savedTypeBounds) {
+      for (val Pair(sym, info) <- savedTypeBounds) {
         if (settings.debug.value) log("resetting " + sym + " to " + info);
         sym.info match {
           case TypeBounds(lo, hi) if (hi <:< lo && lo <:< hi) =>
@@ -393,8 +393,8 @@ trait Contexts requires Analyzer {
       val pre = imp.qual.tpe
       def collect(sels: List[Pair[Name, Name]]): List[ImplicitInfo] = sels match {
         case List() => List()
-        case List{nme.WILDCARD, _} => collectImplicits(pre.implicitMembers, pre)
-        case {from, to} :: sels1 =>
+        case List(Pair(nme.WILDCARD, _)) => collectImplicits(pre.implicitMembers, pre)
+        case Pair(from, to) :: sels1 =>
           var impls = collect(sels1) filter (info => info.name != from)
           if (to != nme.WILDCARD) {
             val sym = imp.importedSymbol(to)
diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
index 3e63401356..91ff898450 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
@@ -50,6 +50,14 @@ trait Infer requires Analyzer {
     } else formals1
   }
 
+  def actualTypes(actuals: List[Type], nformals: int): List[Type] =
+    if (nformals == 1 && actuals.length != 1)
+      List(if (actuals.length == 0) UnitClass.tpe else tupleType(actuals))
+    else actuals
+
+  def actualArgs(pos: PositionType, actuals: List[Tree], nformals: int): List[Tree] =
+    if (nformals == 1 && actuals.length != 1) List(gen.mkTuple(actuals) setPos pos) else actuals
+
   /** A fresh type varable with given type parameter as origin.
    *
    *  @param tparam ...
@@ -134,7 +142,7 @@ trait Infer requires Analyzer {
         val bound: Type = if (up) tparam.info.bounds.hi else tparam.info.bounds.lo
         //Console.println("solveOne0 "+tvar+" "+config+" "+bound);//DEBUG
         var cyclic = false
-        for (val {tvar2, {tparam2, variance2}} <- config) {
+        for (val Pair(tvar2, Pair(tparam2, variance2)) <- config) {
           if (tparam2 != tparam &&
               ((bound contains tparam2) ||
                up && (tparam2.info.bounds.lo =:= tparam.tpe) ||
@@ -170,7 +178,7 @@ trait Infer requires Analyzer {
         assertNonCyclic(tvar)//debug
       }
     }
-    for (val {tvar, {tparam, variance}} <- config)
+    for (val Pair(tvar, Pair(tparam, variance)) <- config)
       solveOne(tvar, tparam, variance)
     tvars map instantiate
   }
@@ -227,11 +235,11 @@ trait Infer requires Analyzer {
         "expression of type " + tree.tpe
       else if (tree.symbol.hasFlag(OVERLOADED))
         "overloaded method " + tree.symbol + " with alternatives " + tree.tpe
-      else (
+      else
         tree.symbol.toString() +
         (if (tree.tpe.paramSectionCount > 0) ": " else " of type ") +
-        tree.tpe
-      )
+        tree.tpe +
+        (if (tree.symbol.name == nme.apply) tree.symbol.locationString else "")
 
     def applyErrorMsg(tree: Tree, msg: String, argtpes: List[Type], pt: Type) = (
       treeSymTypeMsg(tree) + msg + argtpes.mkString("(", ",", ")") +
@@ -295,13 +303,13 @@ trait Infer requires Analyzer {
           explainName(sym1)
           explainName(sym2)
           if (sym1.owner == sym2.owner) sym2.name = newTypeName("(some other)"+sym2.name)
-          {sym1, sym2, name}
+          Triple(sym1, sym2, name)
         }
       }
 
       val result = op
 
-      for (val {sym1, sym2, name} <- patches) {
+      for (val Triple(sym1, sym2, name) <- patches) {
         sym1.name = name
         sym2.name = name
       }
@@ -519,10 +527,11 @@ trait Infer requires Analyzer {
      *  @return            ...
      */
     def isApplicable(undetparams: List[Symbol], ftpe: Type,
-                     argtpes: List[Type], pt: Type): boolean =
+                     argtpes0: List[Type], pt: Type): boolean =
       ftpe match {
         case MethodType(formals0, restpe) =>
-          val formals = formalTypes(formals0, argtpes.length)
+          val formals = formalTypes(formals0, argtpes0.length)
+          val argtpes = actualTypes(argtpes0, formals.length)
           if (undetparams.isEmpty) {
             (formals.length == argtpes.length &&
              isCompatible(argtpes, formals) &&
@@ -539,7 +548,7 @@ trait Infer requires Analyzer {
           }
         case PolyType(tparams, restpe) =>
           val tparams1 = cloneSymbols(tparams)
-          isApplicable(tparams1 ::: undetparams, restpe.substSym(tparams, tparams1), argtpes, pt)
+          isApplicable(tparams1 ::: undetparams, restpe.substSym(tparams, tparams1), argtpes0, pt)
         case ErrorType =>
           true
         case _ =>
@@ -650,13 +659,12 @@ trait Infer requires Analyzer {
      */
     def inferMethodInstance(fn: Tree, undetparams: List[Symbol],
                             args: List[Tree], pt: Type): List[Symbol] = fn.tpe match {
-      case MethodType(formals, restpe) =>
+      case MethodType(formals0, restpe) =>
         try {
-          val argtpes = args map (.tpe.deconst)
+          val formals = formalTypes(formals0, args.length)
+          val argtpes = actualTypes(args map (.tpe.deconst), formals.length)
           val uninstantiated = new ListBuffer[Symbol]
-          val targs = methTypeArgs(
-            undetparams, formalTypes(formals, argtpes.length),
-            restpe, argtpes, pt, uninstantiated)
+          val targs = methTypeArgs(undetparams, formals, restpe, argtpes, pt, uninstantiated)
           checkBounds(fn.pos, NoPrefix, NoSymbol, undetparams, targs, "inferred ")
           //Console.println("UNAPPLY subst type "+undetparams+" to "+targs+" in "+fn+" ( "+args+ ")")
           val treeSubst = new TreeTypeSubstituter(undetparams, targs)
@@ -685,8 +693,8 @@ trait Infer requires Analyzer {
      *        any correspondiong non-variant type arguments of bt1 and bt2 are the same
      */
     def isPopulated(tp1: Type, tp2: Type): boolean = {
-      def isConsistent(tp1: Type, tp2: Type): boolean = {tp1, tp2} match {
-        case {TypeRef(pre1, sym1, args1), TypeRef(pre2, sym2, args2)} =>
+      def isConsistent(tp1: Type, tp2: Type): boolean = Pair(tp1, tp2) match {
+        case Pair(TypeRef(pre1, sym1, args1), TypeRef(pre2, sym2, args2)) =>
           assert(sym1 == sym2)
           pre1 =:= pre2 &&
           !(List.map3(args1, args2, sym1.typeParams) {
@@ -773,9 +781,9 @@ trait Infer requires Analyzer {
         if (settings.debug.value) log("new alias of " + tparam + " = " + tparam.info)
       } else {
         val instType = toOrigin(tvar.constr.inst)
-        val {loBounds, hiBounds} =
-          if (instType != NoType && isFullyDefined(instType)) {List(instType), List(instType)}
-          else {tvar.constr.lobounds, tvar.constr.hibounds}
+        val Pair(loBounds, hiBounds) =
+          if (instType != NoType && isFullyDefined(instType)) Pair(List(instType), List(instType))
+          else Pair(tvar.constr.lobounds, tvar.constr.hibounds)
         val lo = lub(tparam.info.bounds.lo :: loBounds map toOrigin)
         val hi = glb(tparam.info.bounds.hi :: hiBounds map toOrigin)
         if (!(lo <:< hi)) {
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index 162bc87d43..d7025f3dc1 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -219,7 +219,7 @@ trait Namers requires Analyzer {
 
     def skolemize(tparams: List[AbsTypeDef]): unit = {
       val tskolems = newTypeSkolems(tparams map (.symbol))
-      for (val {tparam, tskolem} <- tparams zip tskolems) tparam.symbol = tskolem
+      for (val Pair(tparam, tskolem) <- tparams zip tskolems) tparam.symbol = tskolem
     }
 
     def applicableTypeParams(owner: Symbol): List[Symbol] =
@@ -625,8 +625,8 @@ trait Namers requires Analyzer {
                 }
                 true
               }
-              def checkSelectors(selectors: List[{Name, Name}]): unit = selectors match {
-                case {from, to} :: rest =>
+              def checkSelectors(selectors: List[Pair[Name, Name]]): unit = selectors match {
+                case Pair(from, to) :: rest =>
         	  if (from != nme.WILDCARD && base != ErrorType) {
         	    if (base.member(from) == NoSymbol && base.member(from.toTypeName) == NoSymbol)
         	      context.error(tree.pos, from.decode + " is not a member of " + expr);
@@ -687,12 +687,12 @@ trait Namers requires Analyzer {
                     error(ntree.pos, "duplicate value for element " + name)
                   } else {
                     names -= sym
-                    {sym.name, getConstant(typer.typed(rhs, EXPRmode | CONSTmode, sym.tpe.resultType))}
+                    Pair(sym.name, getConstant(typer.typed(rhs, EXPRmode | CONSTmode, sym.tpe.resultType)))
                   }
                 }
               }
               for (val name <- names) {
-                if (!name.attributes.contains{AnnotationDefaultAttr.tpe, List(), List()}) {
+                if (!name.attributes.contains(Triple(AnnotationDefaultAttr.tpe, List(), List()))) {
                   error(t.pos, "attribute " + tpt.tpe.symbol.fullNameString + " is missing element " + name.name)
                 }
               }
@@ -784,8 +784,8 @@ trait Namers requires Analyzer {
         else if (isFunctionType(tp) &&
                  (!isFunctionType(elemtp) || tp.typeArgs.length > elemtp.typeArgs.length))
           result = true
-        else {tp, elemtp} match {
-          case {TypeRef(pre, sym, args), TypeRef(elempre, elemsym, elemargs)} =>
+        else Pair(tp, elemtp) match {
+          case Pair(TypeRef(pre, sym, args), TypeRef(elempre, elemsym, elemargs)) =>
             if ((sym == elemsym) && (pre =:= elempre) && (args.length == elemargs.length))
               result = List.forall2(elemargs, args) (isContainedIn)
           case _ =>
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 0c1df47925..2afb6dd493 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -100,12 +100,12 @@ abstract class RefChecks extends InfoTransform {
                 else "")))
       }
 
-      def overridesType(tp1: Type, tp2: Type): boolean = {tp1, tp2} match {
-        case {MethodType(List(), rtp1), PolyType(List(), rtp2)} =>
+      def overridesType(tp1: Type, tp2: Type): boolean = Pair(tp1, tp2) match {
+        case Pair(MethodType(List(), rtp1), PolyType(List(), rtp2)) =>
           rtp1 <:< rtp2
-        case {PolyType(List(), rtp1), MethodType(List(), rtp2)} =>
+        case Pair(PolyType(List(), rtp1), MethodType(List(), rtp2)) =>
           rtp1 <:< rtp2
-        case {TypeRef(_, sym, _),  _} if (sym.isModuleClass) =>
+        case Pair(TypeRef(_, sym, _),  _) if (sym.isModuleClass) =>
           overridesType(PolyType(List(), tp1), tp2)
         case _ =>
           tp1 <:< tp2
@@ -375,7 +375,7 @@ abstract class RefChecks extends InfoTransform {
 
       def validateVarianceArgs(tps: List[Type], variance: int, tparams: List[Symbol]): unit =
 	(tps zip tparams) foreach {
-	  case {tp, tparam} => validateVariance(tp, variance * tparam.variance)
+	  case Pair(tp, tparam) => validateVariance(tp, variance * tparam.variance)
 	}
 
       validateVariance(all, variance)
diff --git a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
index 84eb0cc9bf..51ed171076 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
@@ -36,7 +36,7 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT
 
   class SuperAccTransformer(unit: CompilationUnit) extends TypingTransformer(unit) {
     private var validCurrentOwner = true
-    private var accDefs: List[{Symbol, ListBuffer[Tree]}] = List()
+    private var accDefs: List[Pair[Symbol, ListBuffer[Tree]]] = List()
 
     private def accDefBuf(clazz: Symbol) =
       accDefs.dropWhile(._1.!=(clazz)).head._2
@@ -63,7 +63,7 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT
         super.transform(tree)
       case Template(parents, body) =>
 	val ownAccDefs = new ListBuffer[Tree];
-	accDefs = {currentOwner, ownAccDefs} :: accDefs;
+	accDefs = Pair(currentOwner, ownAccDefs) :: accDefs;
 
         // ugly hack... normally, the following line should not be
         // necessary, the 'super' method taking care of that. but because
diff --git a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
index f5999b3582..bd534813c2 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
@@ -81,7 +81,7 @@ trait SyntheticMethods requires Analyzer {
       //val retTpe = lub(accs map (.tpe.resultType))
       val method = syntheticMethod(nme.element, FINAL, MethodType(List(IntClass.tpe), AnyClass.tpe/*retTpe*/))
       typed(DefDef(method, vparamss => Match(Ident(vparamss.head.head), {
-	(for(val {sym,i} <- accs.zipWithIndex) yield {
+	(for(val Pair(sym,i) <- accs.zipWithIndex) yield {
 	  CaseDef(Literal(Constant(i)),EmptyTree, Ident(sym))
 	}):::List(CaseDef(Ident(nme.WILDCARD), EmptyTree,
 		    Throw(New(TypeTree(IndexOutOfBoundsExceptionClass.tpe), List(List(
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index b546d4b8d6..1e645f3baa 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -974,21 +974,21 @@ trait Typers requires Analyzer {
      */
     def computeParamAliases(clazz: Symbol, vparamss: List[List[ValDef]], rhs: Tree): unit = {
       if (settings.debug.value) log("computing param aliases for "+clazz+":"+clazz.primaryConstructor.tpe+":"+rhs);//debug
-      def decompose(call: Tree): {Tree, List[Tree]} = call match {
+      def decompose(call: Tree): Pair[Tree, List[Tree]] = call match {
         case Apply(fn, args) =>
-          val {superConstr, args1} = decompose(fn)
+          val Pair(superConstr, args1) = decompose(fn)
           val formals = fn.tpe.paramTypes
           val args2 = if (formals.isEmpty || formals.last.symbol != RepeatedParamClass) args
                       else args.take(formals.length - 1) ::: List(EmptyTree)
           if (args2.length != formals.length)
             assert(false, "mismatch " + clazz + " " + formals + " " + args2);//debug
-          {superConstr, args1 ::: args2}
+          Pair(superConstr, args1 ::: args2)
         case Block(stats, expr) =>
           decompose(stats.head)
         case _ =>
-          {call, List()}
+          Pair(call, List())
       }
-      val {superConstr, superArgs} = decompose(rhs)
+      val Pair(superConstr, superArgs) = decompose(rhs)
       assert(superConstr.symbol ne null)//debug
       if (superConstr.symbol.isPrimaryConstructor) {
         val superClazz = superConstr.symbol.owner
@@ -1221,16 +1221,16 @@ trait Typers requires Analyzer {
     def typedFunction(fun: Function, mode: int, pt: Type): Tree = {
       val codeExpected = !forCLDC && !forMSIL && (pt.symbol isNonBottomSubClass CodeClass)
 
-      def decompose(pt: Type): {Symbol, List[Type], Type} =
+      def decompose(pt: Type): Triple[Symbol, List[Type], Type] =
         if (isFunctionType(pt)
             ||
             pt.symbol == PartialFunctionClass &&
             fun.vparams.length == 1 && fun.body.isInstanceOf[Match])
-          {pt.symbol, pt.typeArgs.init, pt.typeArgs.last}
+          Triple(pt.symbol, pt.typeArgs.init, pt.typeArgs.last)
         else
-          {FunctionClass(fun.vparams.length), fun.vparams map (x => NoType), WildcardType}
+          Triple(FunctionClass(fun.vparams.length), fun.vparams map (x => NoType), WildcardType)
 
-      val {clazz, argpts, respt} = decompose(if (codeExpected) pt.typeArgs.head else pt)
+      val Triple(clazz, argpts, respt) = decompose(if (codeExpected) pt.typeArgs.head else pt)
 
       if (fun.vparams.length != argpts.length)
         errorTree(fun, "wrong number of parameters; expected = " + argpts.length)
@@ -1381,14 +1381,15 @@ trait Typers requires Analyzer {
           typedApply(tree, adapt(fun, funMode(mode), WildcardType), args1, mode, pt)
         case MethodType(formals0, restpe) =>
           val formals = formalTypes(formals0, args.length)
-          if (formals.length != args.length) {
-            //Console.println(formals.length+" "+args.length);//DEBUG
+          var args1 = actualArgs(tree.pos, args, formals.length)
+          if (formals.length != args1.length) {
+            Console.println(formals+" "+args1);//DEBUG
             errorTree(tree, "wrong number of arguments for "+treeSymTypeMsg(fun))
           } else {
             val tparams = context.undetparams
             context.undetparams = List()
             if (tparams.isEmpty) {
-              val args1 = typedArgs(args, mode, formals0, formals)
+              val args2 = typedArgs(args1, mode, formals0, formals)
               def ifPatternSkipFormals(tp: Type) = tp match {
                 case MethodType(_, rtp) if ((mode & PATTERNmode) != 0) => rtp
                 case _ => tp
@@ -1408,7 +1409,7 @@ trait Typers requires Analyzer {
                        // the compiler thinks, the PLUS method takes only one argument,
                        // but he thinks it's an instance method -> still two ref's on the stack
                        //  -> translated by backend
-                       val rhs = copy.Apply(tree, f, args)
+                       val rhs = copy.Apply(tree, f, args1)
                        return typed(Assign(qual, rhs))
                      }
                   case _ => ()
@@ -1418,9 +1419,9 @@ trait Typers requires Analyzer {
               if (fun.symbol == List_apply && args.isEmpty) {
                 atPos(tree.pos) { gen.mkNil setType restpe }
               } else if ((mode & CONSTmode) != 0 && fun.symbol.owner == PredefModule.tpe.symbol && fun.symbol.name == nme.Array) {
-                val elems = new Array[Constant](args1.length)
+                val elems = new Array[Constant](args2.length)
                 var i = 0;
-                for (val arg <- args1) arg match {
+                for (val arg <- args2) arg match {
                   case Literal(value) =>
                     elems(i) = value
                     i = i + 1
@@ -1430,7 +1431,7 @@ trait Typers requires Analyzer {
                 Literal(arrayConst) setType mkConstantType(arrayConst)
               }
               else
-                constfold(copy.Apply(tree, fun, args1).setType(ifPatternSkipFormals(restpe)))
+                constfold(copy.Apply(tree, fun, args2).setType(ifPatternSkipFormals(restpe)))
             } else {
               assert((mode & PATTERNmode) == 0); // this case cannot arise for patterns
               val lenientTargs = protoTypeArgs(tparams, formals, restpe, pt)
@@ -1447,12 +1448,12 @@ trait Typers requires Analyzer {
                 }
                 arg1
               }
-              val args1 = List.map2(args, formals)(typedArgToPoly)
-              if (args1 exists (.tpe.isError)) setError(tree)
+              val args2 = List.map2(args1, formals)(typedArgToPoly)
+              if (args2 exists (.tpe.isError)) setError(tree)
               else {
-                if (settings.debug.value) log("infer method inst "+fun+", tparams = "+tparams+", args = "+args1.map(.tpe)+", pt = "+pt+", lobounds = "+tparams.map(.tpe.bounds.lo)+", parambounds = "+tparams.map(.info));//debug
-                val undetparams = inferMethodInstance(fun, tparams, args1, pt)
-                val result = typedApply(tree, fun, args1, mode, pt)
+                if (settings.debug.value) log("infer method inst "+fun+", tparams = "+tparams+", args = "+args2.map(.tpe)+", pt = "+pt+", lobounds = "+tparams.map(.tpe.bounds.lo)+", parambounds = "+tparams.map(.info));//debug
+                val undetparams = inferMethodInstance(fun, tparams, args2, pt)
+                val result = typedApply(tree, fun, args2, mode, pt)
                 context.undetparams = undetparams
                 result
               }
@@ -1499,14 +1500,14 @@ trait Typers requires Analyzer {
           val oldArgType = arg.tpe
           if (!isApplicable(List(), unappType, List(arg.tpe), WildcardType)) {
             //Console.println("UNAPP: need to typetest, arg.tpe = "+arg.tpe+", unappType = "+unappType)
-            def freshArgType(tp: Type): {Type, List[Symbol]} = tp match {
+            def freshArgType(tp: Type): Pair[Type, List[Symbol]] = tp match {
               case MethodType(formals, restpe) =>
-                {formals(0), List()}
+                Pair(formals(0), List())
               case PolyType(tparams, restype) =>
                 val tparams1 = cloneSymbols(tparams)
-                {freshArgType(restype)._1.substSym(tparams, tparams1), tparams1}
+                Pair(freshArgType(restype)._1.substSym(tparams, tparams1), tparams1)
             }
-            val {unappFormal, freeVars} = freshArgType(unappType)
+            val Pair(unappFormal, freeVars) = freshArgType(unappType)
             val context1 = context.makeNewScope(context.tree, context.owner)
             freeVars foreach context1.scope.enter
             val typer1 = new Typer(context1)
@@ -1567,12 +1568,12 @@ trait Typers requires Analyzer {
                   error(ntree.pos, "duplicate value for element " + name)
                 } else {
                   names -= sym
-                  {sym.name, getConstant(typed(rhs, EXPRmode | CONSTmode, sym.tpe.resultType))}
+                  Pair(sym.name, getConstant(typed(rhs, EXPRmode | CONSTmode, sym.tpe.resultType)))
                 }
               }
             }
             for (val name <- names) {
-              if (!name.attributes.contains{AnnotationDefaultAttr.tpe, List(), List()}) {
+              if (!name.attributes.contains(Triple(AnnotationDefaultAttr.tpe, List(), List()))) {
                 error(constr.pos, "attribute " + tpt.tpe.symbol.fullNameString + " is missing element " + name.name)
               }
             }
@@ -2151,6 +2152,7 @@ trait Typers requires Analyzer {
           }
 
         case Typed(expr, tpt @ Ident(name)) if (name == nme.WILDCARD_STAR.toTypeName) =>
+          //todo: do this: errorTree(tree, "`: _*' annotation only legal for method arguments")
           val expr1 = typed(expr, mode & stickyModes, seqType(pt))
           expr1.tpe.baseType(SeqClass) match {
             case TypeRef(_, _, List(elemtp)) =>
@@ -2198,12 +2200,12 @@ trait Typers requires Analyzer {
           }
 
         case Super(qual, mix) =>
-          val {clazz, selftype} =
+          val Pair(clazz, selftype) =
             if (tree.symbol != NoSymbol) {
-              {tree.symbol, tree.symbol.thisType}
+              Pair(tree.symbol, tree.symbol.thisType)
             } else {
               val clazzContext = qualifyingClassContext(tree, qual)
-              {clazzContext.owner, clazzContext.prefix}
+              Pair(clazzContext.owner, clazzContext.prefix)
             }
           if (clazz == NoSymbol) setError(tree)
           else {
@@ -2229,12 +2231,12 @@ trait Typers requires Analyzer {
           }
 
         case This(qual) =>
-          val {clazz, selftype} =
+          val Pair(clazz, selftype) =
             if (tree.symbol != NoSymbol) {
-              {tree.symbol, tree.symbol.thisType}
+              Pair(tree.symbol, tree.symbol.thisType)
             } else {
               val clazzContext = qualifyingClassContext(tree, qual)
-              {clazzContext.owner, clazzContext.prefix}
+              Pair(clazzContext.owner, clazzContext.prefix)
             }
           if (clazz == NoSymbol) setError(tree)
           else {
-- 
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