LazyList potentially memory leak?

[xuwei-k]

• scala/scala@f84acc9
• Stream leaks memory #7266

Should we change like this?

--- a/src/library/scala/collection/immutable/LazyList.scala
+++ b/src/library/scala/collection/immutable/LazyList.scala
@@ -564,17 +564,17 @@ object LazyList extends LazyListFactory[LazyList] {
     protected def headDefined: Boolean = false
   }
 
-  final class Cons[A](hd: => A, tl: => LazyList[A]) extends LazyList[A] {
-    private[this] var hdEvaluated: Boolean = false
-    private[this] var tlEvaluated: Boolean = false
+  final class Cons[A](private var hd: () => A, private var tl: () => LazyList[A]) extends LazyList[A] {
     override def isEmpty: Boolean = false
     override lazy val head: A = {
-      hdEvaluated = true
-      hd
+      val result = hd()
+      hd = null
+      result
     }
     override lazy val tail: LazyList[A] = {
-      tlEvaluated = true
-      tl
+      val result = tl()
+      tl = null
+      result
     }
     def force: this.type = {
       // Use standard 2x 1x iterator trick for cycle detection ("those" is slow one)
@@ -596,8 +596,8 @@ object LazyList extends LazyListFactory[LazyList] {
       this
     }
 
-    protected def tailDefined: Boolean = tlEvaluated
-    protected def headDefined: Boolean = hdEvaluated
+    protected def tailDefined: Boolean = tl == null
+    protected def headDefined: Boolean = hd == null
   }

[xuwei-k]

scala/scala@5a985e9#diff-04841eeda02f00638b4cda505dbeafbeR559