Fixes underlying "...

2 files changed, 19 insertions, 6 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/Trees.scala b/src/compiler/scala/tools/nsc/ast/Trees.scala
index 90d1135517..f7c56db113 100644
--- a/src/compiler/scala/tools/nsc/ast/Trees.scala
+++ b/src/compiler/scala/tools/nsc/ast/Trees.scala
@@ -1093,10 +1093,15 @@ trait Trees extends reflect.generic.Trees { self: SymbolTable =>
   def resetLocalAttrs[A<:Tree](x:A): A = { new ResetLocalAttrsTraverser().traverse(x); x }
 
   /** A traverser which resets symbol and tpe fields of all nodes in a given tree
-   *  except for (1) TypeTree nodes, whose <code>.tpe</code> field is kept and
-   *  (2) if a <code>.symbol</code> field refers to a symbol which is defined
+   *  except for (1) TypeTree nodes, whose <code>.tpe</code> field is kept, and
+   *  (2) This(pkg) nodes, where pkg refers to a package symbol -- their attributes are kept, and
+   *  (3) if a <code>.symbol</code> field refers to a symbol which is defined
    *  outside the tree, it is also kept.
    *
+   *  (2) is necessary because some This(pkg) are generated where pkg is not
+   *  an enclosing package.n In that case, resetting the symbol would cause the
+   *  next type checking run to fail. See #3152.
+   *
    *  (bq:) This traverser has mutable state and should be discarded after use
    */
   private class ResetAttrsTraverser extends Traverser {
@@ -1108,15 +1113,15 @@ trait Trees extends reflect.generic.Trees { self: SymbolTable =>
       tree match {
         case _: DefTree | Function(_, _) | Template(_, _, _) =>
           resetDef(tree)
-        case _ =>
-          if (tree.hasSymbol && isLocal(tree.symbol)) tree.symbol = NoSymbol
-      }
-      tree match {
+          tree.tpe = null
         case tpt: TypeTree =>
           if (tpt.wasEmpty) tree.tpe = null
+        case This(_) if tree.symbol != null && tree.symbol.isPackageClass =>
+          ;
         case EmptyTree =>
           ;
         case _ =>
+          if (tree.hasSymbol && isLocal(tree.symbol)) tree.symbol = NoSymbol
           tree.tpe = null
       }
       super.traverse(tree)
diff --git a/test/pending/neg/t3152.scala b/test/pending/neg/t3152.scala
new file mode 100644
index 0000000000..27a314c484
--- /dev/null
+++ b/test/pending/neg/t3152.scala
@@ -0,0 +1,8 @@
+package test
+
+object NotEnclosing {
+  def main(args : Array[String]) : Unit = {}
+  def compare[T](x: Ordered[T], y: Ordered[T]) = error("")
+  def mkEx: Ordered[_] = error("")
+  compare(mkEx, mkEx)
+}