using System;

using System.Collections.Generic;

using System.Linq;

​

#nullable enable

​

int val = 2;

_ = val.AsNullable()!.Value;

​

public static class Test

{

    public static T? AsNullable<T>(this T t) where T : struct => (T?) t;

    public static IEnumerable<T> WhereNotNull<T>(this IEnumerable<T?> ts) where T : struct => ts.Where(t => t.HasValue).Select(x => x!.Value);

}