Fix size update on `mutable.TreeMap#clear()`

The previous implementation has a major bug - although `clear()` sets the root node to `null`, the `size` attribute of the `Tree` was not updated. This effectively meant that even after a `map.clear()`, a call to `map.size` would still yield the old size of the map.

The scalacheck test suite was updated to contemplate this issue.

1 files changed, 2 insertions, 2 deletions

diff --git a/test/files/scalacheck/MutableTreeMap.scala b/test/files/scalacheck/MutableTreeMap.scala
index ac073b1c42..b072307a63 100644
--- a/test/files/scalacheck/MutableTreeMap.scala
+++ b/test/files/scalacheck/MutableTreeMap.scala
@@ -163,7 +163,7 @@ package scala.collection.mutable {
 
     property("clear") = forAll { (map: mutable.TreeMap[K, V]) =>
       map.clear()
-      map.isEmpty
+      map.isEmpty && map.size == 0
     }
 
     property("serializable") = forAll { (map: mutable.TreeMap[K, V]) =>
@@ -303,7 +303,7 @@ package scala.collection.mutable {
     property("clear") = forAll { (map: mutable.TreeMap[K, V], from: Option[K], until: Option[K]) =>
       val mapView = map.rangeImpl(from, until)
       mapView.clear()
-      map.isEmpty && mapView.isEmpty
+      map.isEmpty && mapView.isEmpty && map.size == 0 && mapView.size == 0
     }
 
     property("serializable") = forAll { (map: mutable.TreeMap[K, V], from: Option[K], until: Option[K]) =>