benchmark works with findAll but crashed weirdly with lazyFindAll

cp-demo/BinarySortedLists.scala

+import cp.Definitions._
+import cp.Terms._
+
+object BinarySortedLists {
+  def main(args : Array[String]) : Unit = {
+    val inRange : Constraint1[Int] = ((x : Int) => x >= 0 && x <= 1)
+  
+    val sortedLists =
+      for(x <- inRange.lazyFindAll;
+        y <- inRange.lazyFindAll if y >= x;
+        z <- inRange.lazyFindAll if z >= y)
+      yield {
+        x.value; y.value; z.value;  
+        List(x, y, z)
+      }
+  
+    sortedLists.foreach(println(_))
+  }
+}