Code inspection: Redundant nullable attribute

This inspection reports nullable flow-analysis attributes such as [MaybeNull], [NotNull], or [MaybeNullWhen(...)] when the target type and existing contracts already make the attribute unnecessary. In that case, the attribute adds noise without strengthening the API contract.

                #nullable enable annotations
                using System.Diagnostics.CodeAnalysis;
                class C
                {
                    [return: NotNull]
                    public extern string? GetText();
                }
            

                #nullable enable annotations
                class C
                {
                    public extern string? GetText();
                }
            

This commonly happens when the type itself already communicates the same nullability information.

13 April 2026