diff --git a/src/Movere/Common/MaybeNullWhenFalseAttribute.cs b/src/Movere/Common/MaybeNullWhenFalseAttribute.cs
index 4f2dcf3..d880f91 100644
--- a/src/Movere/Common/MaybeNullWhenFalseAttribute.cs
+++ b/src/Movere/Common/MaybeNullWhenFalseAttribute.cs
@@ -1,7 +1,11 @@
-namespace System.Runtime.CompilerServices
+#if NETSTANDARD2_0
+
+namespace System.Runtime.CompilerServices
 {
     [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false)]
     internal sealed class MaybeNullWhenFalseAttribute : Attribute
     {
     }
 }
+
+#endif