Fix Enumerator.Current handling in SortedDictionary<,>

* System.Collections.Generic/RBTree.cs (NodeEnumerator.check_current):
 New helper.
(NodeEnumerator.Current): Don't check invariants.
* SortedDictionary.cs (Enumerator.Current): Likewise.
(ValueCollection.Enumerator.Current): Likewise.
(KeyCollection.Enumerator.Current): Likewise.

* Test/System.Collections.Generic/SortedDictionaryTest.cs
(Enumerator_Current, KeyEnumerator_Current, ValueEnumerator_Current): New tests.

svn path=/trunk/mcs/; revision=139115

2 files changed, 107 insertions, 0 deletions

diff --git a/mcs/class/System/Test/System.Collections.Generic/ChangeLog b/mcs/class/System/Test/System.Collections.Generic/ChangeLog
index 9901e47c71b..35dea1ecd55 100644
--- a/mcs/class/System/Test/System.Collections.Generic/ChangeLog
+++ b/mcs/class/System/Test/System.Collections.Generic/ChangeLog
@@ -1,3 +1,8 @@
+2009-07-31  Raja R Harinath  <harinath@hurrynot.org>
+
+	* SortedDictionaryTest.cs (Enumerator_Current): New test.
+	(KeyEnumerator_Current, ValueEnumerator_Current): Likewise.
+
 2009-07-14 Gonzalo Paniagua Javier <gonzalo@novell.com>
 
 	* SortedListTest.cs: new tests for bug #521750 provided by
diff --git a/mcs/class/System/Test/System.Collections.Generic/SortedDictionaryTest.cs b/mcs/class/System/Test/System.Collections.Generic/SortedDictionaryTest.cs
index af38b8dc7f8..f293f329a20 100644
--- a/mcs/class/System/Test/System.Collections.Generic/SortedDictionaryTest.cs
+++ b/mcs/class/System/Test/System.Collections.Generic/SortedDictionaryTest.cs
@@ -463,6 +463,108 @@ namespace MonoTests.System.Collections.Generic
 			d.Add (4, "D");
 			e.MoveNext ();
 		}
+
+
+		delegate void D ();
+		bool Throws (D d)
+		{
+			try {
+				d ();
+				return false;
+			} catch {
+				return true;
+			}
+		}
+
+		[Test]
+		// based on #491858, #517415
+		public void Enumerator_Current ()
+		{
+			var e1 = new SortedDictionary<int,int>.Enumerator ();
+			Assert.IsFalse (Throws (delegate { var x = e1.Current; }));
+
+			var d = new SortedDictionary<int,int> ();
+			var e2 = d.GetEnumerator ();
+			Assert.IsFalse (Throws (delegate { var x = e2.Current; }));
+			e2.MoveNext ();
+			Assert.IsFalse (Throws (delegate { var x = e2.Current; }));
+			e2.Dispose ();
+			Assert.IsFalse (Throws (delegate { var x = e2.Current; }));
+
+			var e3 = ((IEnumerable<KeyValuePair<int,int>>) d).GetEnumerator ();
+			Assert.IsFalse (Throws (delegate { var x = e3.Current; }));
+			e3.MoveNext ();
+			Assert.IsFalse (Throws (delegate { var x = e3.Current; }));
+			e3.Dispose ();
+			Assert.IsFalse (Throws (delegate { var x = e3.Current; }));
+
+			var e4 = ((IEnumerable) d).GetEnumerator ();
+			Assert.IsTrue (Throws (delegate { var x = e4.Current; }));
+			e4.MoveNext ();
+			Assert.IsTrue (Throws (delegate { var x = e4.Current; }));
+			((IDisposable) e4).Dispose ();
+			Assert.IsTrue (Throws (delegate { var x = e4.Current; }));
+		}
+
+		[Test]
+		// based on #491858, #517415
+		public void KeyEnumerator_Current ()
+		{
+			var e1 = new SortedDictionary<int,int>.KeyCollection.Enumerator ();
+			Assert.IsFalse (Throws (delegate { var x = e1.Current; }));
+
+			var d = new SortedDictionary<int,int> ().Keys;
+			var e2 = d.GetEnumerator ();
+			Assert.IsFalse (Throws (delegate { var x = e2.Current; }));
+			e2.MoveNext ();
+			Assert.IsFalse (Throws (delegate { var x = e2.Current; }));
+			e2.Dispose ();
+			Assert.IsFalse (Throws (delegate { var x = e2.Current; }));
+
+			var e3 = ((IEnumerable<int>) d).GetEnumerator ();
+			Assert.IsFalse (Throws (delegate { var x = e3.Current; }));
+			e3.MoveNext ();
+			Assert.IsFalse (Throws (delegate { var x = e3.Current; }));
+			e3.Dispose ();
+			Assert.IsFalse (Throws (delegate { var x = e3.Current; }));
+
+			var e4 = ((IEnumerable) d).GetEnumerator ();
+			Assert.IsTrue (Throws (delegate { var x = e4.Current; }));
+			e4.MoveNext ();
+			Assert.IsTrue (Throws (delegate { var x = e4.Current; }));
+			((IDisposable) e4).Dispose ();
+			Assert.IsTrue (Throws (delegate { var x = e4.Current; }));
+		}
+
+		[Test]
+		// based on #491858, #517415
+		public void ValueEnumerator_Current ()
+		{
+			var e1 = new SortedDictionary<int,int>.ValueCollection.Enumerator ();
+			Assert.IsFalse (Throws (delegate { var x = e1.Current; }));
+
+			var d = new SortedDictionary<int,int> ().Values;
+			var e2 = d.GetEnumerator ();
+			Assert.IsFalse (Throws (delegate { var x = e2.Current; }));
+			e2.MoveNext ();
+			Assert.IsFalse (Throws (delegate { var x = e2.Current; }));
+			e2.Dispose ();
+			Assert.IsFalse (Throws (delegate { var x = e2.Current; }));
+
+			var e3 = ((IEnumerable<int>) d).GetEnumerator ();
+			Assert.IsFalse (Throws (delegate { var x = e3.Current; }));
+			e3.MoveNext ();
+			Assert.IsFalse (Throws (delegate { var x = e3.Current; }));
+			e3.Dispose ();
+			Assert.IsFalse (Throws (delegate { var x = e3.Current; }));
+
+			var e4 = ((IEnumerable) d).GetEnumerator ();
+			Assert.IsTrue (Throws (delegate { var x = e4.Current; }));
+			e4.MoveNext ();
+			Assert.IsTrue (Throws (delegate { var x = e4.Current; }));
+			((IDisposable) e4).Dispose ();
+			Assert.IsTrue (Throws (delegate { var x = e4.Current; }));
+		}
 	}
 
 	class ReverseComparer<T> : IComparer<T>