JetBrains Rider 2026.1 Help

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

This inspection reports a LINQ query that casts elements with as and then counts non-null results. The same count can be expressed more directly with OfType<T>().Count().

Example

int count = items.Select(x => x as string).Count(y => y != null);
int count = items.OfType<string>().Count();

Quick-fix

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

29 March 2026
Code inspection: Replace with OfType<T>().Any() (replace with OfType<T>().Any(..))Code inspection: Replace with OfType<T>().Count() (replace with OfType<T>().Count(..))