fix for #1721

2 files changed, 17 insertions, 10 deletions

diff --git a/src/library/scala/Seq.scala b/src/library/scala/Seq.scala
index 0d1306b07f..18b8dac676 100644
--- a/src/library/scala/Seq.scala
+++ b/src/library/scala/Seq.scala
@@ -470,15 +470,8 @@ trait Seq[+A] extends AnyRef with PartialFunction[Int, A] with Collection[A] {
   /** @return true if this sequence end with that sequence
    *  @see String.endsWith
    */
-  def endsWith[B](that: Seq[B]): Boolean = {
-    val length = this.length
-    val j = that.elements
-    var i = 0
-    var result = true
-    while (result && i < length && j.hasNext)
-      result = apply(length - i - 1) == j.next
-    result && !j.hasNext
-  }
+  def endsWith[B](that: Seq[B]): Boolean =
+    drop(length - that.length).sameElements(that)
 
   /**
    * Searches for the argument sequence in the receiver object, returning
diff --git a/test/files/run/lists.scala b/test/files/run/lists.scala
index 665cf51970..93848da25f 100644
--- a/test/files/run/lists.scala
+++ b/test/files/run/lists.scala
@@ -15,7 +15,8 @@ object Test extends TestConsoleMain {
   def suite = new TestSuite(
     Test1, //count, exists, filter, ..
     Test2, //#468
-    Test3  //#1691
+    Test3, //#1691
+    Test4  //#1721
   )
 }
 
@@ -126,3 +127,16 @@ object Test3 extends TestCase("t1691") with Assert {
 		 List(10, 8, 6, 4, 2))
   }
 }
+
+object Test4 extends TestCase("t1721") with Assert {
+  override def enableStackTrace = false
+  override def runTest {
+    assertTrue(List(1,2,3).endsWith(List(2,3)))
+    assertFalse(List(1,2,3).endsWith(List(1,3)))
+    assertTrue(List(1,2,3).endsWith(List()))
+    assertFalse(List(1,2,3).endsWith(List(0,1,2,3)))
+    assertTrue(List(1,2,3).endsWith(List(1,2,3)))
+    assertFalse(List().endsWith(List(1,2,3)))
+    assertTrue(List().endsWith(List()))
+  }
+}