diff --git a/Directory.Build.props b/Directory.Build.props
index 3305fdccc..457faceb4 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -10,7 +10,7 @@
         <Deterministic>true</Deterministic>
         <TargetFramework>net8.0</TargetFramework>
         <Nullable>enable</Nullable>
-        <WarningsAsErrors>CS8002,nullable</WarningsAsErrors>
+        <WarningsAsErrors>CS9057,CS8002,nullable</WarningsAsErrors>
         <EnableSourceControlManagerQueries>true</EnableSourceControlManagerQueries>
         <SignAssembly>True</SignAssembly>
         <RootPath>$(MSBuildThisFileDirectory)</RootPath>