Decode names of package members on enter

Avoids mutable names and the hassles associated with them.

Author: odersky

compiler/src/dotty/tools/dotc/core/SymDenotations.scala

@@ -125,7 +125,6 @@ object SymDenotations {
 
     // ------ Getting and setting fields -----------------------------
 
-    private[this] var myName = initName
     private[this] var myFlags: FlagSet = adaptFlags(initFlags)
     private[this] var myInfo: Type = initInfo
     private[this] var myPrivateWithin: Symbol = initPrivateWithin

compiler/src/dotty/tools/dotc/core/SymbolLoaders.scala

@@ -40,7 +40,7 @@ class SymbolLoaders {
   def enterClass(
       owner: Symbol, name: PreName, completer: SymbolLoader,
       flags: FlagSet = EmptyFlags, scope: Scope = EmptyScope)(implicit ctx: Context): Symbol = {
-    val cls = ctx.newClassSymbol(owner, name.toTypeName, flags, completer, assocFile = completer.sourceFileOrNull)
+    val cls = ctx.newClassSymbol(owner, name.toTypeName.unmangleClassName.decode, flags, completer, assocFile = completer.sourceFileOrNull)
     enterNew(owner, cls, completer, scope)
   }
 
@@ -50,7 +50,7 @@ class SymbolLoaders {
       owner: Symbol, name: PreName, completer: SymbolLoader,
       modFlags: FlagSet = EmptyFlags, clsFlags: FlagSet = EmptyFlags, scope: Scope = EmptyScope)(implicit ctx: Context): Symbol = {
     val module = ctx.newModuleSymbol(
-      owner, name.toTermName, modFlags, clsFlags,
+      owner, name.toTermName.decode, modFlags, clsFlags,
       (module, _) => completer.proxy withDecls newScope withSourceModule (_ => module),
       assocFile = completer.sourceFileOrNull)
     enterNew(owner, module, completer, scope)
@@ -166,13 +166,7 @@ class SymbolLoaders {
       override def lookupEntry(name: Name)(implicit ctx: Context): ScopeEntry = {
         val mangled = name.mangled
         val e = super.lookupEntry(mangled)
-        if (e != null) {
-          // Eagerly update symbol's name to undecoded name to avpid the name
-          // spearding to types.
-          if (name.toSimpleName != mangled && e.sym.initialDenot.name == mangled)
-            e.sym.initialDenot.name = name
-          e
-        }
+        if (e != null) e
         else if (_sourceModule.initialDenot.name == nme.scala_ && _sourceModule == defn.ScalaPackageVal &&
                  name.isTypeName && name.isSyntheticFunction)
           newScopeEntry(defn.newFunctionNTrait(name.asTypeName))

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -436,7 +436,6 @@ class TreeUnpickler(reader: TastyReader, nameAtRef: NameRef => TermName, posUnpi
         roots.find(root => (root.owner eq ctx.owner) && root.name.mangled == mname) match {
           case Some(rootd) =>
             pickling.println(i"overwriting ${rootd.symbol} # ${rootd.hashCode}")
-            rootd.name = name
             rootd.info = adjustIfModule(
                 new Completer(ctx.owner, subReader(start, end)) with SymbolLoaders.SecondCompleter)
             rootd.flags = flags &~ Touched // allow one more completion

compiler/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala

@@ -460,7 +460,6 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
     //if (isModuleClassRoot) println(s"moduleClassRoot of $moduleClassRoot found at $readIndex, flags = $flags") // !!! DEBUG
 
     def completeRoot(denot: ClassDenotation, completer: LazyType): Symbol = {
-      denot.name = name
       denot.setFlag(flags)
       denot.resetFlag(Touched) // allow one more completion
       denot.info = completer