psalm-plugin-laravel/stubs/HasOne.stubphp

<?php

namespace Illuminate\Database\Eloquent\Relations;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Collection;
use Illuminate\Database\Eloquent\Relations\Concerns\SupportsDefaultModels;

/**
* @template TRelatedModel of Model
* @template-extends HasOneOrMany<TRelatedModel>
* @mixin \Illuminate\Database\Eloquent\Builder<TRelatedModel>
*/
class HasOne extends HasOneOrMany
{
    use SupportsDefaultModels;

    /**
     * @param  \Illuminate\Database\Eloquent\Model  $parent
     * @return \Illuminate\Database\Eloquent\Model
     * @psalm-return TRelatedModel
     */
    public function newRelatedInstanceFor(Model $parent) { }
}