diff --git a/src/Shared/JSInterop/JSCallResultTypeHelper.cs b/src/Shared/JSInterop/JSCallResultTypeHelper.cs
index 82c3920c7210..8bf1a547fc1b 100644
--- a/src/Shared/JSInterop/JSCallResultTypeHelper.cs
+++ b/src/Shared/JSInterop/JSCallResultTypeHelper.cs
@@ -1,15 +1,28 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Reflection;
+
 namespace Microsoft.JSInterop
 {
     internal static class JSCallResultTypeHelper
     {
+        // We avoid using Assembly.GetExecutingAssembly() because this is shared code.
+        private static readonly Assembly _currentAssembly = typeof(JSCallResultType).Assembly;
+
         public static JSCallResultType FromGeneric<TResult>()
-            => typeof(TResult) == typeof(IJSObjectReference)
-            || typeof(TResult) == typeof(IJSInProcessObjectReference)
-            || typeof(TResult) == typeof(IJSUnmarshalledObjectReference) ?
-                JSCallResultType.JSObjectReference :
-                JSCallResultType.Default;
+        {
+            if (typeof(TResult).Assembly == _currentAssembly
+                && (typeof(TResult) == typeof(IJSObjectReference)
+                || typeof(TResult) == typeof(IJSInProcessObjectReference)
+                || typeof(TResult) == typeof(IJSUnmarshalledObjectReference)))
+            {
+                return JSCallResultType.JSObjectReference;
+            }
+            else
+            {
+                return JSCallResultType.Default;
+            }
+        }
     }
 }