Null coalescing assignment

The null coalescing operator, ??, has been extended in C# 8 to support assignment. A popular usage for the null coalescing operator involves the parameter checks at the beginning of a method, like in the following example:

class Person
{
    public Person(string firstName, string lastName, int age)
    {
        this.FirstName = firstName ?? throw new ArgumentNullException(nameof(firstName));
        this.LastName = lastName ?? throw new ArgumentNullException(nameof(lastName));
        this.Age = age;
    }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public int Age { get; set; }
}

The new assignment allows us to reassign the reference whenever it is null, as demonstrated...