Code inspection: Replace with OfType<T>().FirstOrDefault() (replace with OfType<T>().FirstOrDefault(..))

This inspection reports a LINQ query that casts elements with as, filters out null, and then looks for the first element matching an additional condition. The same query is easier to read with OfType<T>().FirstOrDefault(...).

Example

                var first = items.Select(x => x as Person).FirstOrDefault(y => y != null && y.IsActive);
            

var first = items.OfType<Person>().FirstOrDefault(y => y.IsActive);

Quick-fix

Replace the Select(... as T).FirstOrDefault(y => y != null && ...) pattern with OfType<T>().FirstOrDefault(...).

29 March 2026