Add sanity check for overrides (#2793)

Make sure that MethodImpls point to an interface that the type
implements or a base type that is inherited from.

2 files changed, 52 insertions, 0 deletions

diff --git a/test/Mono.Linker.Tests.Cases.Expectations/Assertions/KeptOverrideAttribute.cs b/test/Mono.Linker.Tests.Cases.Expectations/Assertions/KeptOverrideAttribute.cs
new file mode 100644
index 000000000..62bfd0c15
--- /dev/null
+++ b/test/Mono.Linker.Tests.Cases.Expectations/Assertions/KeptOverrideAttribute.cs
@@ -0,0 +1,27 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+
+namespace Mono.Linker.Tests.Cases.Expectations.Assertions
+{
+	/// <summary>
+	/// Used to ensure that a method should keep an 'override' annotation for a method in the supplied base type.
+	/// The absence of this attribute does not enforce that the override is removed -- this is different from other Kept attributes
+	/// To enforce the removal of an override, use <see cref="RemovedOverrideAttribute"/>.
+	/// Fails in tests if the method doesn't have the override method in the original or linked assembly.
+	/// </summary>
+	/// <seealso cref="RemovedOverrideAttribute" />
+	[AttributeUsage (AttributeTargets.Method, AllowMultiple = true, Inherited = false)]
+	public class KeptOverrideAttribute : KeptAttribute
+	{
+		public Type TypeWithOverriddenMethodDeclaration;
+
+		public KeptOverrideAttribute (Type typeWithOverriddenMethod)
+		{
+			if (typeWithOverriddenMethod == null)
+				throw new ArgumentNullException (nameof (typeWithOverriddenMethod));
+			TypeWithOverriddenMethodDeclaration = typeWithOverriddenMethod;
+		}
+	}
+}
\ No newline at end of file
diff --git a/test/Mono.Linker.Tests.Cases.Expectations/Assertions/RemovedOverrideAttribute.cs b/test/Mono.Linker.Tests.Cases.Expectations/Assertions/RemovedOverrideAttribute.cs
new file mode 100644
index 000000000..c15cf9a9e
--- /dev/null
+++ b/test/Mono.Linker.Tests.Cases.Expectations/Assertions/RemovedOverrideAttribute.cs
@@ -0,0 +1,25 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+
+namespace Mono.Linker.Tests.Cases.Expectations.Assertions
+{
+	/// <Summary>
+	/// Used to ensure that a method should remove an 'override' annotation for a method in the supplied base type.
+	/// Fails in tests if the method has the override method in the linked assembly,
+	///		or if the override is not found in the original assembly
+	/// </Summary>
+	/// <seealso cref="KeptOverrideAttribute" />
+	[AttributeUsage (AttributeTargets.Method, AllowMultiple = true, Inherited = false)]
+	public class RemovedOverrideAttribute : BaseInAssemblyAttribute
+	{
+		public Type TypeWithOverriddenMethodDeclaration;
+		public RemovedOverrideAttribute (Type typeWithOverriddenMethod)
+		{
+			if (typeWithOverriddenMethod == null)
+				throw new ArgumentException ("Value cannot be null or empty.", nameof (typeWithOverriddenMethod));
+			TypeWithOverriddenMethodDeclaration = typeWithOverriddenMethod;
+		}
+	}
+}
\ No newline at end of file