diff --git a/src/core/Microsoft.Scripting/Hosting/DocumentationOperations.cs b/src/core/Microsoft.Scripting/Hosting/DocumentationOperations.cs
index 52fa4d6d..626abdb8 100644
--- a/src/core/Microsoft.Scripting/Hosting/DocumentationOperations.cs
+++ b/src/core/Microsoft.Scripting/Hosting/DocumentationOperations.cs
@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
+
 #if FEATURE_REMOTING
 using System.Runtime.Remoting;
 #else
@@ -55,7 +57,7 @@ public ICollection<OverloadDoc> GetOverloads(ObjectHandle value) {
 
         // TODO: Figure out what is the right lifetime
         public override object InitializeLifetimeService() {
-            return null;
+            return base.InitializeLifetimeService();
         }
 #endif
  }
diff --git a/src/core/Microsoft.Scripting/Runtime/DocumentationProvider.cs b/src/core/Microsoft.Scripting/Runtime/DocumentationProvider.cs
index 61b51009..c2ab0a24 100644
--- a/src/core/Microsoft.Scripting/Runtime/DocumentationProvider.cs
+++ b/src/core/Microsoft.Scripting/Runtime/DocumentationProvider.cs
@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
+
 using System.Collections.Generic;
 
 using Microsoft.Scripting.Hosting;
diff --git a/src/core/Microsoft.Scripting/Runtime/SourceStringContentProvider.cs b/src/core/Microsoft.Scripting/Runtime/SourceStringContentProvider.cs
index e37cb7e1..f136da76 100644
--- a/src/core/Microsoft.Scripting/Runtime/SourceStringContentProvider.cs
+++ b/src/core/Microsoft.Scripting/Runtime/SourceStringContentProvider.cs
@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information.
 
+#nullable enable
+
 using System;
 using System.IO;