wrong field is never assigned suggestion

Hi I am using version 4.5.1231.7 and for the code bellow

        private string nameWithSR;
        public string NameWithSR
        {
            get { return nameWithSR; }
            set
            {

                this.SetProperty(()=>NameWithSR,()=>nameWithSR,value);
            }
        }

i get a field is never assigned suggestion. Which is wrong cause I assign the value of  nameWithSR inside SetProperty method