feat: add HasCollection trait

Author: calebdw

src/Illuminate/Database/Eloquent/HasCollection.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Illuminate\Database\Eloquent;
+
+/**
+ * @template TCollection of \Illuminate\Database\Eloquent\Collection
+ */
+trait HasCollection
+{
+    /**
+     * Create a new Eloquent Collection instance.
+     *
+     * @param  array<array-key, \Illuminate\Database\Eloquent\Model>  $models
+     * @return TCollection
+     */
+    public function newCollection(array $models = [])
+    {
+        return parent::newCollection($models);
+    }
+}

src/Illuminate/Database/Eloquent/Model.php

@@ -218,6 +218,13 @@ abstract class Model implements Arrayable, ArrayAccess, CanBeEscapedWhenCastToSt
      */
     protected static string $builder = Builder::class;
 
+    /**
+     * The Eloquent collection class to use for the model.
+     *
+     * @var class-string<\Illuminate\Database\Eloquent\Collection<*, *>>
+     */
+    protected static string $collection = Collection::class;
+
     /**
      * The name of the "created at" column.
      *
@@ -1598,7 +1605,7 @@ protected function newBaseQueryBuilder()
      */
     public function newCollection(array $models = [])
     {
-        return new Collection($models);
+        return new static::$collection($models);
     }
 
     /**

types/Database/Eloquent/Model.php

@@ -3,6 +3,7 @@
 namespace Illuminate\Types\Model;
 
 use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Database\Eloquent\HasCollection;
 use Illuminate\Database\Eloquent\Model;
 use User;
 
@@ -32,7 +33,7 @@ function test(User $user, Post $post, Comment $comment): void
     assertType('Illuminate\Database\Eloquent\Relations\MorphMany<Illuminate\Notifications\DatabaseNotification, User>', $user->notifications());
 
     assertType('Illuminate\Database\Eloquent\Collection<int, User>', $user->newCollection([new User()]));
-    assertType('Illuminate\Database\Eloquent\Collection<string, Illuminate\Types\Model\Post>', $post->newCollection(['foo' => new Post()]));
+    assertType('Illuminate\Types\Model\Posts<(int|string), Illuminate\Types\Model\Post>', $post->newCollection(['foo' => new Post()]));
     assertType('Illuminate\Types\Model\Comments', $comment->newCollection([new Comment()]));
 
     assertType('bool', $user->restore());
@@ -41,6 +42,18 @@ function test(User $user, Post $post, Comment $comment): void
 }
 
 class Post extends Model
+{
+    /** @use HasCollection<Posts<array-key, static>> */
+    use HasCollection;
+
+    protected static string $collection = Posts::class;
+}
+
+/**
+ * @template TKey of array-key
+ * @template TModel of Post
+ * @extends Collection<TKey, TModel> */
+class Posts extends Collection
 {
 }