diff --git a/test/DefaultCluster.Tests/CodeGenTests/IRuntimeCodeGenGrain.cs b/test/DefaultCluster.Tests/CodeGenTests/IRuntimeCodeGenGrain.cs
index bc3da0c948..0c501987de 100644
--- a/test/DefaultCluster.Tests/CodeGenTests/IRuntimeCodeGenGrain.cs
+++ b/test/DefaultCluster.Tests/CodeGenTests/IRuntimeCodeGenGrain.cs
@@ -8,21 +8,22 @@ namespace Tester.CodeGenTests
     using Orleans;
     using Orleans.Providers;
 
-    public interface ISomeInterface<in T>
+    // Regression test for explicit interface method implementations https://github.com/dotnet/orleans/issues/8991
+    public interface IExplicitOverridesTestGenericBase<in T>
     {
         Task M(T arg);
     }
 
-    public interface IBase : ISomeInterface<object>;
+    public interface IExplicitOverridesTestBase : IExplicitOverridesTestGenericBase<object>;
 
-    public interface IDerived : IBase, ISomeInterface<string>
+    public interface IExplicitOverridesTestDerived : IExplicitOverridesTestBase, IExplicitOverridesTestGenericBase<string>
     {
-        Task ISomeInterface<object>.M(object obj) => M(obj);
+        Task IExplicitOverridesTestGenericBase<object>.M(object obj) => M(obj);
     }
 
-    public interface ISomeGrainWithExplicitImplementation : IDerived, IGrainWithGuidKey;
+    public interface IExplicitOverridesTestImplementation : IExplicitOverridesTestDerived, IGrainWithGuidKey;
 
-    public class SomeGrain : Grain, ISomeGrainWithExplicitImplementation
+    public class ExplicitOverridesTestGrain : Grain, IExplicitOverridesTestImplementation
     {
         public Task M(string arg)
         {
@@ -30,6 +31,8 @@ public Task M(string arg)
         }
     }
 
+    // End regression test for https://github.com/dotnet/orleans/issues/8991
+
     public interface IGrainWithGenericMethods : IGrainWithGuidKey
     {
         Task<Type[]> GetTypesExplicit<T, U, V>();