Collect references as well as definitions for computing ids of a tree

Author: odersky

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

@@ -667,7 +667,7 @@ object Symbols {
         case None =>
           val idSet = mutable.SortedSet[String]()
           tree.foreachSubTree {
-            case tree: tpd.RefTree => idSet += tree.name.toString
+            case tree: tpd.NameTree => idSet += tree.name.toString
             case _ =>
           }
           val ids = idSet.toArray

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

@@ -10,6 +10,7 @@ import util.Positions._
 import util.{SourceFile, NoSource}
 import Annotations.Annotation
 import classfile.ClassfileParser
+import Names.SimpleName
 
 object DottyUnpickler {