Manage multiple id.

Id.cs

// 複数のIDを管理するテク
//  【C# 9.0】 Source Generator回 - ufcpp  https://youtu.be/QXT-TSvIbbY?t=5816

var person0 = new Person(0);
var person1 = new Person(1);
var shop0 = new Shop(0);

System.Console.WriteLine("Check Id0 : " + (person0.Id == person1.Id));

// 以下だと型が違うので比較できない
//System.Console.WriteLine("Check Id1 : " + (person0.Id == shop0.Id));

// 無理やりキャストすれば比較できんこともない
System.Console.WriteLine("Check Id2 : " + ((int)person0.Id == (int)shop0.Id));

class Person
{
    public Id<Person> Id { get; init; }
    public Person(int id) => Id = new Id<Person>(id);
}

class Shop
{
    public Id<Shop> Id { get; init; }
    public Shop(int id) => Id = (Id<Shop>)id;
}

public struct Id<T> : System.IEquatable<Id<T>>
{
    public readonly int Value { get; init; }
    public Id(int value) => Value = value;
    public static bool Equals(Id<T> left, Id<T> right) => left.Value == right.Value;
    public readonly bool Equals(Id<T> other) => Equals(this, other);
    public readonly override bool Equals(object? obj) => obj is Id<T> other && Equals(this, other);
    public readonly override int GetHashCode() => Value.GetHashCode();
    public static bool operator ==(Id<T> left, Id<T> right) => Equals(left, right);
    public static bool operator !=(Id<T> left, Id<T> right) => !Equals(left, right);

    public static explicit operator Id<T>(int value) => new Id<T>() { Value = value };
    public static explicit operator int(Id<T> value) => value.Value;
}