Revise qualified names

1. Fix problem in fullNameSeparated
2. Revise expandedName operations

Author: odersky

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

@@ -107,7 +107,7 @@ object SymDenotations {
   class SymDenotation private[SymDenotations] (
     symbol: Symbol,
     ownerIfExists: Symbol,
-    initName: Name,
+    final val name: Name,
     initFlags: FlagSet,
     initInfo: Type,
     initPrivateWithin: Symbol = NoSymbol) extends SingleDenotation(symbol) {
@@ -131,12 +131,6 @@ object SymDenotations {
     private[this] var myPrivateWithin: Symbol = initPrivateWithin
     private[this] var myAnnotations: List[Annotation] = Nil
 
-    /** The name of the symbol */
-    def name = myName
-
-    /** Update the name; only called when unpickling top-level classes */
-    def name_=(n: Name) = myName = n
-
     /** The owner of the symbol; overridden in NoDenotation */
     def owner: Symbol = ownerIfExists
 
@@ -1218,12 +1212,12 @@ object SymDenotations {
   class ClassDenotation private[SymDenotations] (
     symbol: Symbol,
     ownerIfExists: Symbol,
-    initName: Name,
+    name: Name,
     initFlags: FlagSet,
     initInfo: Type,
     initPrivateWithin: Symbol,
     initRunId: RunId)
-    extends SymDenotation(symbol, ownerIfExists, initName, initFlags, initInfo, initPrivateWithin) {
+    extends SymDenotation(symbol, ownerIfExists, name, initFlags, initInfo, initPrivateWithin) {
 
     import util.LRUCache