Obsolete InternalTestFailureException and GenericParameterHelper

src/TestFramework/TestFramework/Constants.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+namespace Microsoft.VisualStudio.TestTools.UnitTesting;
+
+/// <summary>
+/// Constants used throughout.
+/// </summary>
+internal static class Constants
+{
+    internal const string PublicTypeObsoleteMessage = "We will remove or hide this type starting with v4. If you are using this type, reach out to our team on https://github.com/microsoft/testfx.";
+}

src/TestFramework/TestFramework/Exceptions/InternalTestFailureException.cs

@@ -10,6 +10,13 @@ namespace Microsoft.VisualStudio.TestTools.UnitTesting;
 /// This class is only added to preserve source compatibility with the V1 framework.
 /// For all practical purposes either use AssertFailedException/AssertInconclusiveException.
 /// </remarks>
+#if RELEASE
+#if NET6_0_OR_GREATER
+[Obsolete(Constants.PublicTypeObsoleteMessage, DiagnosticId = "MSTESTOBS")]
+#else
+[Obsolete(Constants.PublicTypeObsoleteMessage)]
+#endif
+#endif
 [Serializable]
 public class InternalTestFailureException : UnitTestAssertException
 {

src/TestFramework/TestFramework/GenericParameterHelper.cs

@@ -15,7 +15,13 @@ namespace Microsoft.VisualStudio.TestTools.UnitTesting;
 // This next suppression could mask a problem, since Equals and CompareTo may not agree!
 [SuppressMessage("Microsoft.Design", "CA1036:OverrideMethodsOnComparableTypes", Justification = "Compat reasons.")]
 [SuppressMessage("Design", "CA1010:Generic interface should also be implemented", Justification = "Part of the public API")]
-
+#if RELEASE
+#if NET6_0_OR_GREATER
+[Obsolete(Constants.PublicTypeObsoleteMessage, DiagnosticId = "MSTESTOBS")]
+#else
+[Obsolete(Constants.PublicTypeObsoleteMessage)]
+#endif
+#endif
 // GenericParameterHelper in full CLR version also implements ICloneable, but we don't have ICloneable in core CLR
 public class GenericParameterHelper : IComparable, IEnumerable
 {