Fixed initialization for vars initialized to th...

Fixed initialization for vars initialized to the default value (inside
traits). Should fix failing test 'bugs.scala'.

6 files changed, 15 insertions, 33 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index 0c734d23bf..23fb13277d 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -1952,6 +1952,7 @@ trait Parsers extends NewScanners with MarkupParsers {
           if (!tp.isEmpty && newmods.hasFlag(Flags.MUTABLE) &&
               (lhs.toList forall (_.isInstanceOf[Ident])) && inToken == USCORE) {
             inNextToken
+            newmods = newmods | Flags.DEFAULTINIT
             EmptyTree
           } else {
             expr()
diff --git a/src/compiler/scala/tools/nsc/symtab/Flags.scala b/src/compiler/scala/tools/nsc/symtab/Flags.scala
index f8ea35df70..b2819712ef 100644
--- a/src/compiler/scala/tools/nsc/symtab/Flags.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Flags.scala
@@ -37,6 +37,7 @@ object Flags extends Enumeration {
   final val BYNAMEPARAM   = 0x00010000    // parameter is by name
   final val CONTRAVARIANT = 0x00020000    // symbol is a contravariant type variable
   final val LABEL         = 0x00020000    // method symbol is a label. Set by TailCall
+  final val DEFAULTINIT   = 0x00020000    // field is initialized to the default value (used by checkinit)
   final val INCONSTRUCTOR = 0x00020000    // class symbol is defined in this/superclass
                                           // constructor.
   final val ABSOVERRIDE   = 0x00040000    // combination of abstract & override
@@ -189,7 +190,7 @@ object Flags extends Enumeration {
       case DEPRECATED    => "<deprecated>"
 
       case COVARIANT     => "<covariant/captured/byname>"
-      case CONTRAVARIANT => "<contravariant/label/inconstr>"
+      case CONTRAVARIANT => "<contravariant/label/inconstr/defaultinit>"
       case ABSOVERRIDE   => "abstract override"
       case LOCAL         => "<local>"
 
diff --git a/src/compiler/scala/tools/nsc/symtab/Symbols.scala b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
index b5df166790..2baeee7fff 100644
--- a/src/compiler/scala/tools/nsc/symtab/Symbols.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Symbols.scala
@@ -203,7 +203,8 @@ trait Symbols {
     final def isLocalDummy = isTerm && nme.isLocalDummyName(name)
     final def isMethod = isTerm && hasFlag(METHOD)
     final def isSourceMethod = isTerm && (flags & (METHOD | STABLE)) == METHOD
-    final def isLabel = isTerm && hasFlag(LABEL)
+    final def isLabel = isMethod && !hasFlag(ACCESSOR) && hasFlag(LABEL)
+    final def isInitializedToDefault = !isType && (getFlag(DEFAULTINIT | ACCESSOR) == (DEFAULTINIT | ACCESSOR))
     final def isClassConstructor = isTerm && (name == nme.CONSTRUCTOR)
     final def isMixinConstructor = isTerm && (name == nme.MIXIN_CONSTRUCTOR)
     final def isConstructor = isTerm && (name == nme.CONSTRUCTOR) || (name == nme.MIXIN_CONSTRUCTOR)
diff --git a/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala b/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala
index 77f5cf60aa..85031d706c 100644
--- a/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala
+++ b/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala
@@ -58,7 +58,7 @@ abstract class AddInterfaces extends InfoTransform {
   private def isInterfaceMember(sym: Symbol): Boolean = {
     sym.isType ||
     { sym.info; // to set lateMETHOD flag if necessary
-      sym.isMethod && !(sym hasFlag (PRIVATE | BRIDGE | LABEL)) &&
+      sym.isMethod && !sym.isLabel && !(sym hasFlag (PRIVATE | BRIDGE)) &&
       !sym.isConstructor && !sym.isImplOnly
     }
   }
diff --git a/src/compiler/scala/tools/nsc/transform/Constructors.scala b/src/compiler/scala/tools/nsc/transform/Constructors.scala
index 50be9600b2..9bccf5c95f 100644
--- a/src/compiler/scala/tools/nsc/transform/Constructors.scala
+++ b/src/compiler/scala/tools/nsc/transform/Constructors.scala
@@ -190,12 +190,9 @@ abstract class Constructors extends Transform {
           // the initializer goes as an assignment into the constructor
           // if the val def is an early initialized or a parameter accessor, it goes
           // before the superclass constructor call, otherwise it goes after.
-          // Lazy vals don't get the assignment in the constructor. Fields initialized
-          // to default values are not eliminated until the mixin phase, when
-          // checked initializers are added
+          // Lazy vals don't get the assignment in the constructor.
           if (!stat.symbol.tpe.isInstanceOf[ConstantType]) {
-            if ((rhs != EmptyTree || !stat.symbol.originalName.startsWith(nme.OUTER))
-                && !stat.symbol.hasFlag(LAZY)) {
+            if (rhs != EmptyTree && !stat.symbol.hasFlag(LAZY)) {
               val rhs1 = intoConstructor(stat.symbol, rhs);
               (if (canBeMoved(stat)) constrPrefixBuf else constrStatBuf) += mkAssign(
                 stat.symbol, rhs1)
diff --git a/src/compiler/scala/tools/nsc/transform/Mixin.scala b/src/compiler/scala/tools/nsc/transform/Mixin.scala
index f22cde9669..5dd4fa83e7 100644
--- a/src/compiler/scala/tools/nsc/transform/Mixin.scala
+++ b/src/compiler/scala/tools/nsc/transform/Mixin.scala
@@ -628,9 +628,6 @@ abstract class Mixin extends InfoTransform {
         localTyper.typed(atPos(pos)(Block(List(result), retVal)))
       }
 
-      /** Fields that are initialized to their default value. They don't need a checked accessor. */
-      val initToDefault = new mutable.HashSet[Symbol]
-
       /** Complete lazy field accessors. Applies only to classes, for it's own (non inherited) lazy fields.
        *  If 'checkinit' is enabled, getters that check for the initialized bit are generated, and
        *  the class constructor is changed to set the initialized bits.
@@ -659,7 +656,7 @@ abstract class Mixin extends InfoTransform {
               }
               copy.DefDef(stat, mods, name, tp, vp, tpt, rhs1)
 
-          case DefDef(mods, name, tp, vp, tpt, rhs) if sym.isClassConstructor =>
+          case DefDef(mods, name, tp, vp, tpt, rhs) if sym.isConstructor =>
             copy.DefDef(stat, mods, name, tp, vp, tpt, addInitBits(clazz, rhs))
 
           case _ => stat
@@ -671,7 +668,7 @@ abstract class Mixin extends InfoTransform {
       def needsInitFlag(sym: Symbol) = {
         val res = (settings.checkInit.value
            && sym.isGetter
-           && !initToDefault(sym)
+           && !sym.isInitializedToDefault
            && !sym.hasFlag(PARAMACCESSOR)
            && !sym.accessed.hasFlag(PRESUPER)
            && !sym.isOuterAccessor)
@@ -679,7 +676,7 @@ abstract class Mixin extends InfoTransform {
         if (settings.debug.value) {
           println("needsInitFlag(" + sym.fullNameString + "): " + res)
           println("\tsym.isGetter: " + sym.isGetter)
-          println("\t!initToDefault(sym): " + !initToDefault(sym))
+          println("\t!isInitializedToDefault: " + !sym.isInitializedToDefault + sym.hasFlag(DEFAULTINIT) + sym.hasFlag(ACCESSOR) + sym.isTerm)
           println("\t!sym.hasFlag(PARAMACCESSOR): " + !sym.hasFlag(PARAMACCESSOR))
           //println("\t!sym.accessed.hasFlag(PRESUPER): " + !sym.accessed.hasFlag(PRESUPER))
           println("\t!sym.isOuterAccessor: " + !sym.isOuterAccessor)
@@ -706,7 +703,9 @@ abstract class Mixin extends InfoTransform {
                 } else {
                   List(stat)
                 }
-
+              case Apply(setter @ Select(Ident(self), _), List(EmptyTree)) if setter.symbol.isSetter =>
+                // remove initialization for default values
+                List()
               case _ => List(stat)
             }
             }
@@ -751,23 +750,6 @@ abstract class Mixin extends InfoTransform {
         }
       }
 
-      // Look for fields that are initialized to the default value
-      // They won't get init fields.
-      new Traverser {
-        override def traverse(tree: Tree): Unit = tree match {
-          case DefDef(mods, name, tparams, vparamss, tpt, rhs) if tree.symbol.isClassConstructor =>
-            val Block(stats, _) = rhs
-            for (s <- stats) s match {
-              case Assign(f @ Select(This(_), _), EmptyTree) =>
-                val getter = clazz.info.decl(nme.getterName(f.symbol.name))
-                if (getter != NoSymbol)
-                  initToDefault += getter
-              case _ => ()
-            }
-          case _ => super.traverse(tree)
-        }
-      }.traverseTrees(stats)
-
       buildFieldPositions(clazz)
       // begin addNewDefs
       var stats1 = addCheckedGetters(clazz, stats)
@@ -826,7 +808,7 @@ abstract class Mixin extends InfoTransform {
                       } else
                         init
                   }
-                } else if (!sym.hasFlag(LAZY) && settings.checkInit.value) {
+                } else if (!sym.hasFlag(LAZY) && needsInitFlag(sym)) {
                   mkCheckedAccessor(clazz,  accessedRef, fieldOffset(sym), sym.pos)
                 } else
                   gen.mkCheckInit(accessedRef)