Made presentation type checker idempotent and r...

Made presentation type checker idempotent and removed code in Global
that was needed to work around non-idempotency.

Author: odersky

src/compiler/scala/tools/nsc/interactive/Global.scala

@@ -114,7 +114,7 @@ self =>
       while(true)
         try {
           try {
-            pollForWork()
+            pollForWork(old.pos)
 	  } catch {
             case ex : Throwable =>
 	      if (context.unit != null) integrateNew()
@@ -176,7 +176,7 @@ self =>
    *  Then, poll for exceptions and execute them.
    *  Then, poll for work reload/typedTreeAt/doFirst commands during background checking.
    */
-  def pollForWork() {
+  def pollForWork(pos: Position) {
     scheduler.pollInterrupt() match {
       case Some(ir) =>
 	try {
@@ -185,7 +185,7 @@ self =>
 	} finally {
 	  activeLocks -= 1
 	}
-        pollForWork()
+        pollForWork(pos)
       case _ =>
     }
 
@@ -219,7 +219,7 @@ self =>
       logreplay("workitem", scheduler.nextWorkItem()) match {
         case Some(action) =>
           try {
-            debugLog("picked up work item: "+action)
+            debugLog("picked up work item at "+pos+": "+action)
             action()
             debugLog("done with work item: "+action)
           } finally {
@@ -282,7 +282,7 @@ self =>
       try {
         while (true) {
           logreplay("wait for more work", { scheduler.waitForMoreWork(); true })
-          pollForWork()
+          pollForWork(NoPosition)
           debugLog("got more work")
           while (outOfDate) {
             try {
@@ -359,7 +359,7 @@ self =>
    */
   def typeCheck(unit: RichCompilationUnit) {
     debugLog("type checking: "+unit)
-    if (currentlyChecked == Some(unit) || unit.status > JustParsed) reset(unit)
+    //if (currentlyChecked == Some(unit) || unit.status > JustParsed) reset(unit) // not deeded for idempotent type checker phase
     if (unit.status == NotLoaded) parse(unit)
     currentlyChecked = Some(unit)
     currentTyperRun.typeCheck(unit)
@@ -412,9 +412,11 @@ self =>
     } catch {
       case CancelException =>
         ;
+/* Commented out. Typing should always cancel requests
       case ex @ FreshRunReq =>
         scheduler.postWorkItem(() => respondGradually(response)(op))
         throw ex
+*/
       case ex =>
         response raise ex
         throw ex
@@ -459,7 +461,7 @@ self =>
       unit.targetPos = pos
       try {
         debugLog("starting targeted type check")
-        newTyperRun()
+        //newTyperRun()   // not deeded for idempotent type checker phase
         typeCheck(unit)
         println("tree not found at "+pos)
         EmptyTree
@@ -477,7 +479,7 @@ self =>
     val unit = unitOf(source)
     if (forceReload) reset(unit)
     if (unit.status <= JustParsed) {
-      newTyperRun()
+      //newTyperRun()   // not deeded for idempotent type checker phase
       typeCheck(unit)
     }
     unit.body
@@ -678,10 +680,10 @@ self =>
   class TyperRun extends Run {
     // units is always empty
 
-    /** canRedefine is used to detect double declarations in multiple source files.
+    /** canRedefine is used to detect double declarations of classes and objects
+     *  in multiple source files.
      *  Since the IDE rechecks units several times in the same run, these tests
      *  are disabled by always returning true here.
-     *  (I think we don't need that anymore)
      */
     override def canRedefine(sym: Symbol) = true
 

src/compiler/scala/tools/nsc/typechecker/Namers.scala

@@ -173,10 +173,10 @@ trait Namers { self: Analyzer =>
       if (!(sym.isSourceMethod && sym.owner.isClass && !sym.owner.isPackageClass)) {
         var prev = scope.lookupEntry(sym.name)
         if ((prev ne null) && prev.owner == scope && conflict(sym, prev.sym)) {
-           doubleDefError(sym.pos, prev.sym)
-           sym setInfo ErrorType
-           scope unlink prev.sym // let them co-exist...
-           scope enter sym
+          doubleDefError(sym.pos, prev.sym)
+          sym setInfo ErrorType
+          scope unlink prev.sym // let them co-exist...
+          scope enter sym
         } else scope enter sym
       } else scope enter sym
     }
@@ -338,13 +338,32 @@ trait Namers { self: Analyzer =>
       } else setInfo(sym)(ltype)
     }
 
+    def enterIfNotThere(sym: Symbol) {
+      val scope = context.scope
+      var e = scope.lookupEntry(sym.name)
+      while ((e ne null) && (e.owner eq scope) && (e.sym ne sym)) e = e.tail
+      if (!((e ne null) && (e.owner eq scope))) context.scope.enter(sym)
+    }
+
     def enterSym(tree: Tree): Context = {
       def finishWith(tparams: List[TypeDef]) { enterSymFinishWith(tree, tparams) }
       def finish = finishWith(Nil)
       def sym = tree.symbol
-      if (sym != NoSymbol)
+      if (sym != NoSymbol) {
+        if (forInteractive && sym != null && sym.owner.isTerm) {
+          // this logic is needed in case typer was interrupted half way through and then comes
+          // back to do the tree again. In that case the definitions that were already
+          // attributed as well as any default parameters of such methods need to be
+          // re-entered in the current scope.
+          enterIfNotThere(sym)
+          if (sym.isLazy) {
+            val acc = sym.lazyAccessor
+            if (acc != NoSymbol) enterIfNotThere(acc)
+          }
+          defaultParametersOfMethod(sym) foreach enterIfNotThere
+        }
         return this.context
-
+      }
       try {
         val owner = context.owner
         tree match {

src/compiler/scala/tools/nsc/typechecker/Typers.scala

@@ -1798,23 +1798,9 @@ trait Typers extends Modes {
      */
     def typedBlock(block: Block, mode: Int, pt: Type): Block = {
       val syntheticPrivates = new ListBuffer[Symbol]
-      def enterIfNotThere(sym: Symbol) {
-        var e = context.scope.lookupEntry(sym.name)
-        while ((e ne null) && (e.sym ne sym)) e = e.tail
-        if (e eq null) context.scope.enter(sym)
-      }
       try {
         namer.enterSyms(block.stats)
-        for (stat <- block.stats) {
-          if (forInteractive && stat.isDef) {
-            // this logic is needed in case typer was interrupted half way through a block and then comes
-            // back to do the block again. In that case the definitions that were already attributed as well as any
-            // default parameters of such methods need to be re-entered in the current scope.
-            enterIfNotThere(stat.symbol)
-            defaultParametersOfMethod(stat.symbol) foreach enterIfNotThere
-          }
-          enterLabelDef(stat)
-        }
+        for (stat <- block.stats) enterLabelDef(stat)
 
         if (phaseId(currentPeriod) <= currentRun.typerPhase.id) {
           // This is very tricky stuff, because we are navigating
@@ -1888,6 +1874,13 @@ trait Typers extends Modes {
         error(x.pos, "_* may only come last")
 
       val pat1: Tree = typedPattern(cdef.pat, pattpe)
+
+      if (forInteractive) {
+        for (bind @ Bind(name, _) <- cdef.pat)
+          if (name.toTermName != nme.WILDCARD && bind.symbol != null && bind.symbol != NoSymbol)
+            namer.enterIfNotThere(bind.symbol)
+      }
+
       val guard1: Tree = if (cdef.guard == EmptyTree) EmptyTree
                          else typed(cdef.guard, BooleanClass.tpe)
       var body1: Tree = typed(cdef.body, pt)