diff --git a/tools/common/Rewriter.cs b/tools/common/Rewriter.cs
index b9cd49713f..17f7393a35 100644
--- a/tools/common/Rewriter.cs
+++ b/tools/common/Rewriter.cs
@@ -20,7 +20,6 @@ namespace ClassRedirector {
 		const string classPtrName = "class_ptr";
 		CSToObjCMap map;
 		string pathToXamarinAssembly;
-		string? outputDirectory = null;
 		Dictionary<string, FieldDefinition> csTypeToFieldDef = new Dictionary<string, FieldDefinition> ();
 		IEnumerable<AssemblyDefinition> assemblies;
 		AssemblyDefinition xamarinAssembly;
@@ -328,11 +327,6 @@ namespace ClassRedirector {
 			}
 		}
 
-		string ToOutputFileName (string pathToInputFileName)
-		{
-			return Path.Combine (outputDirectory, Path.GetFileName (pathToInputFileName));
-		}
-
 		void MarkForSave (AssemblyDefinition assembly)
 		{
 			var annotations = linkContext.Annotations;
diff --git a/tools/dotnet-linker/dotnet-linker.csproj b/tools/dotnet-linker/dotnet-linker.csproj
index 66ff6ea83c..c7f09e9d87 100644
--- a/tools/dotnet-linker/dotnet-linker.csproj
+++ b/tools/dotnet-linker/dotnet-linker.csproj
@@ -4,6 +4,7 @@
     <RootNamespace>dotnet_linker</RootNamespace>
     <DefineConstants>$(DefineConstants);BUNDLER</DefineConstants>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <WarningsAsErrors>nullable</WarningsAsErrors>
   </PropertyGroup>
 
   <Import Project="..\..\eng\Versions.props" />