Extension methods to create simple code around working with WeakReferences referencing UnityEngine.Objects.

WeakReferenceExtensions.cs

using UnityEngine;

/// <summary>
/// Extension methods to create simple code around working with WeakReferences referencing UnityEngine.Objects.
/// </summary>
public static class WeakReferenceExtensions
{
    /// <summary>
    /// Destroys the referenced object if it still exists.
    /// Does nothing if no object is referenced or the referenced object is already destroyed.
    /// </summary>
    /// <param name="obj">The object to destroy.</param>
    public static void Destroy<T>(this System.WeakReference<T> obj) where T : Object
    {
        if (obj != null && obj.TryGetTarget(out var target) && Exists(target))
        {
            Object.Destroy(target);
        }
    }

    /// <summary>
    /// Destroys the referenced component's GameObject if it still exists.
    /// Does nothing if no component is referenced or the referenced component's GameObject is already destroyed.
    /// </summary>
    /// <param name="obj">The object to destroy.</param>
    public static void DestroyGameObject<T>(this System.WeakReference<T> obj) where T : Component
    {
        if (obj != null && obj.TryGetTarget(out var target) && Exists(target) && Exists(target.gameObject))
        {
            Object.Destroy(target.gameObject);
        }
    }

    /// <summary>
    /// Checks whether an object is referenced, and whether that object isn't destroyed.
    /// </summary>
    /// <param name="obj">The object to check.</param>
    /// <returns>True if a WeakReference is passed which references an object that is not destroyed.</returns>
    public static bool Exists<T>(this System.WeakReference<T> obj) where T : Object
    {
        return obj != null && obj.TryGetTarget(out var target) && Exists(target);
    }

    private static bool Exists(Object obj)
    {
        return obj != null;
    }
}