"'With' Expression Support for Immutable Structs"

public readonly struct User {
	public string Name { get; init; }
	public int Age { get; init; }
}

// ...

var user = new User { Name = "Ben", Age = 31 };
var birthdayBoy = user with { Age = user.Age + 1 };
Console.WriteLine(birthdayBoy.Name + " is now " + birthdayBoy.Age); // Prints "Ben is now 32"