RequireImplementorsAttribute

Description

When the interface type is marked, all types implementing that interface will be marked.

using System;
using UnityEngine;
using UnityEngine.Scripting;

public class NewBehaviourScript : MonoBehaviour
{
    void Start()
    {
        IFoo ifoo = new Foo();
    }
}

[RequireImplementors]
interface IFoo {}

class Foo : IFoo {}

// UnusedFoo is not used, however, it will survive managed code stripping due to IFoo having the [RequireImplementors] attribute.
class UnusedFoo : IFoo
{
    // Note that unused members of UnusedFoo will still be removed by managed code stripping
    public static void UnusedMethod() {}
}

// IBar is not used so it will be removed by managed code stripping
[RequireImplementors]
interface IBar {}

// Because IBar is not used, the [RequireImplementors] attribute on IBar has no impact.  UnusedBar will also be removed.
class UnusedBar : IBar {}