1 files changed, 27 insertions, 0 deletions
diff --git a/src/mscorlib/src/System/Collections/IEqualityComparer.cs b/src/mscorlib/src/System/Collections/IEqualityComparer.cs
new file mode 100644
index 0000000000..50c732f47c
--- /dev/null
+++ b/src/mscorlib/src/System/Collections/IEqualityComparer.cs
@@ -0,0 +1,27 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+/*============================================================
+**
+** Interface:  IEqualityComparer
+**
+** 
+** 
+**
+** Purpose: A mechanism to expose a simplified infrastructure for 
+**          Comparing objects in collections.
+**
+** 
+===========================================================*/
+namespace System.Collections {
+    
+    using System;
+    // An IEqualityComparer is a mechanism to consume custom performant comparison infrastructure
+    // that can be consumed by some of the common collections.
+    [System.Runtime.InteropServices.ComVisible(true)]
+    public interface IEqualityComparer {
+        bool Equals(Object x, Object y);
+        int GetHashCode(Object obj);        
+    }
+}