public ITaskItem[]? Sources
        {
            set
            {
                if (UsedCommandLineTool)
                {
                    NormalizePaths(value!); // PROTOTYPE(NullableDogfood): value set should be non-null
                }

                _store[nameof(Sources)] = value;
            }
            get { return (ITaskItem[])_store[nameof(Sources)]; }
        }