Fix List.LastIndexOf () on empty lists. Fixes #2558.

2 files changed, 8 insertions, 0 deletions

diff --git a/mcs/class/corlib/System.Collections.Generic/List.cs b/mcs/class/corlib/System.Collections.Generic/List.cs
index 7646b777ba7..c666eea72be 100644
--- a/mcs/class/corlib/System.Collections.Generic/List.cs
+++ b/mcs/class/corlib/System.Collections.Generic/List.cs
@@ -467,6 +467,8 @@ namespace System.Collections.Generic {
 
 		public int LastIndexOf (T item)
 		{
+			if (_size == 0)
+				return -1;
 			return Array.LastIndexOf<T> (_items, item, _size - 1, _size);
 		}
 		
diff --git a/mcs/class/corlib/Test/System.Collections.Generic/ListTest.cs b/mcs/class/corlib/Test/System.Collections.Generic/ListTest.cs
index 366f270bf79..d33699ecdb8 100644
--- a/mcs/class/corlib/Test/System.Collections.Generic/ListTest.cs
+++ b/mcs/class/corlib/Test/System.Collections.Generic/ListTest.cs
@@ -1307,6 +1307,12 @@ namespace MonoTests.System.Collections.Generic {
 				Assert.IsTrue (e is ArgumentException, "#10");
 			}
 		}
+
+		[Test]
+		public void LastIndexOfEmpty_2558 () {
+			var l = new List<int> ();
+			Assert.AreEqual (-1, l.IndexOf (-1));
+		}
 	}
 }
 #endif