Don't populate 'originalOwner' in presentation ...

Don't populate 'originalOwner' in presentation compiler runs. This is
a source of memory leaks, as the map is never cleared. A better, more
consistent mechanism should be developed for such maps, and ensure they
are cleared on a new Run, or in resetTyper. no review.

2 files changed, 16 insertions, 2 deletions

diff --git a/src/compiler/scala/reflect/internal/Required.scala b/src/compiler/scala/reflect/internal/Required.scala
index 73b739a319..d1501c29c2 100644
--- a/src/compiler/scala/reflect/internal/Required.scala
+++ b/src/compiler/scala/reflect/internal/Required.scala
@@ -14,4 +14,8 @@ trait Required { self: SymbolTable =>
   val gen: TreeGen { val global: Required.this.type }
 
   def settings: MutableSettings
+
+  def forInteractive: Boolean
+
+  def forScaladoc: Boolean
 }
diff --git a/src/compiler/scala/reflect/internal/Symbols.scala b/src/compiler/scala/reflect/internal/Symbols.scala
index 141c197a22..8704eb4bec 100644
--- a/src/compiler/scala/reflect/internal/Symbols.scala
+++ b/src/compiler/scala/reflect/internal/Symbols.scala
@@ -587,8 +587,13 @@ trait Symbols /* extends reflect.generic.Symbols*/ { self: SymbolTable =>
 
     def owner: Symbol = rawowner
     final def owner_=(owner: Symbol) {
-      if (originalOwner contains this) ()
-      else originalOwner(this) = rawowner
+      // don't keep the original owner in presentation compiler runs
+      // (the map will grow indefinitely, and the only use case is the
+      // backend).
+      if (!forInteractive) {
+        if (originalOwner contains this) ()
+        else originalOwner(this) = rawowner
+      }
 
       rawowner = owner
     }
@@ -1319,8 +1324,13 @@ trait Symbols /* extends reflect.generic.Symbols*/ { self: SymbolTable =>
     /** Return the original enclosing method of this symbol. It should return
      *  the same thing as enclMethod when called before lambda lift,
      *  but it preserves the original nesting when called afterwards.
+     *
+     *  @note This method is NOT available in the presentation compiler run. The
+     *        originalOwner map is not populated for memory considerations (the symbol
+     *        may hang on to lazy types and in turn to whole (outdated) compilation units.
      */
     def originalEnclosingMethod: Symbol = {
+      assert(!forInteractive, "originalOwner is not kept in presentation compiler runs.")
       if (isMethod) this
       else {
         val owner = originalOwner.getOrElse(this, rawowner)