Closes 2926. Review by milesabin.

3 files changed, 24 insertions, 9 deletions

diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 76fa2ade93..1fc6098c3f 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -726,6 +726,13 @@ class Global(var settings: Settings, var reporter: Reporter) extends SymbolTable
       else if (sym.isModuleClass) compiles(sym.sourceModule)
       else false
 
+    /** Opposite of compiles, but is overridden in interactive
+     *  notCompiles is used to detect double declarations in multiple source files.
+     *  Since the IDE rechecks units several times in the same run, it should
+     *  always return true there.
+     */
+    def notCompiles(sym: Symbol) = !compiles(sym)
+
     // --------------- Compilation methods ----------------------------
 
     /** Compile list of source files */
diff --git a/src/compiler/scala/tools/nsc/interactive/Global.scala b/src/compiler/scala/tools/nsc/interactive/Global.scala
index 0a8477a489..9ed8b5076e 100644
--- a/src/compiler/scala/tools/nsc/interactive/Global.scala
+++ b/src/compiler/scala/tools/nsc/interactive/Global.scala
@@ -467,11 +467,19 @@ self =>
   class TyperRun extends Run {
     // units is always empty
 
-    //override def compiles(sym: Symbol) = false
+    /** notCompiles is used to detect double declarations in multiple source files.
+     *  Since the IDE rechecks units several times in the same run, these tests
+     *  are disabled by always returning true here.
+     */
+    override def notCompiles(sym: Symbol) = true
 
-    def typeCheck(unit: CompilationUnit): Unit = applyPhase(typerPhase, unit)
+    def typeCheck(unit: CompilationUnit): Unit = {
+      applyPhase(typerPhase, unit)
+    }
 
-    def enterNames(unit: CompilationUnit): Unit = applyPhase(namerPhase, unit)
+    def enterNames(unit: CompilationUnit): Unit = {
+      applyPhase(namerPhase, unit)
+    }
 
     /** Return fully attributed tree at given position
      *  (i.e. largest tree that's contained by position)
@@ -503,7 +511,6 @@ self =>
     def typedTree(unit: RichCompilationUnit): Tree = {
       assert(unit.status >= JustParsed)
       unit.targetPos = NoPosition
-      symSource.clear()
       typeCheck(unit)
       unit.body
     }
@@ -512,7 +519,6 @@ self =>
      *  @return true iff typechecked correctly
      */
     private def applyPhase(phase: Phase, unit: CompilationUnit) {
-      symSource.clear()
       val oldSource = reporter.getSource
       reporter.withSource(unit.source) {
         atPhase(phase) { phase.asInstanceOf[GlobalPhase] applyPhase unit }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index abeab40991..71d325d2c5 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -197,7 +197,7 @@ trait Namers { self: Analyzer =>
 
     def enterClassSymbol(tree : ClassDef): Symbol = {
       var c: Symbol = context.scope.lookup(tree.name)
-      if (c.isType && c.owner.isPackageClass && context.scope == c.owner.info.decls && !currentRun.compiles(c)) {
+      if (c.isType && c.owner.isPackageClass && context.scope == c.owner.info.decls && currentRun.notCompiles(c)) {
         updatePosFlags(c, tree.pos, tree.mods.flags)
         setPrivateWithin(tree, c, tree.mods)
       } else {
@@ -214,7 +214,7 @@ trait Namers { self: Analyzer =>
         }
         clazz.sourceFile = file
         if (clazz.sourceFile ne null) {
-          assert(!currentRun.compiles(clazz) || clazz.sourceFile == currentRun.symSource(c));
+          assert(currentRun.notCompiles(clazz) || clazz.sourceFile == currentRun.symSource(c));
           currentRun.symSource(c) = clazz.sourceFile
         }
       }
@@ -229,7 +229,7 @@ trait Namers { self: Analyzer =>
       var m: Symbol = context.scope.lookup(tree.name)
       val moduleFlags = tree.mods.flags | MODULE | FINAL
       if (m.isModule && !m.isPackage && inCurrentScope(m) &&
-          (!currentRun.compiles(m) || (m hasFlag SYNTHETIC))) {
+          (currentRun.notCompiles(m) || (m hasFlag SYNTHETIC))) {
         updatePosFlags(m, tree.pos, moduleFlags)
         setPrivateWithin(tree, m, tree.mods)
         context.unit.synthetics -= m
@@ -288,7 +288,9 @@ trait Namers { self: Analyzer =>
     def ensureCompanionObject(tree: ClassDef, creator: => Tree): Symbol = {
       val m: Symbol = context.scope.lookup(tree.name.toTermName).filter(! _.isSourceMethod)
       if (m.isModule && inCurrentScope(m) && currentRun.compiles(m)) m
-      else enterSyntheticSym(creator)
+      else
+        /*util.trace("enter synthetic companion object for "+currentRun.compiles(m)+":")*/(
+        enterSyntheticSym(creator))
     }
 
     private def enterSymFinishWith(tree: Tree, tparams: List[TypeDef]) {