Code to accompany the 'Reusable Validation Rules with Laravel Form Requests' post (https://stidges.com/reusable-validation-rules-with-laravel-form-requests)

Request.php

<?php

namespace App\Http\Requests;

use Illuminate\Foundation\Http\FormRequest;
use Illuminate\Validation\Validator;

abstract class Request extends FormRequest
{
    /**
     * Apply the trait rules to the validator.
     *
     * @param  \Illuminate\Validation\Validator  $validator
     * @return void
     */
    public function withValidator(Validator $validator)
    {
        if ($rules = $this->getTraitRules()) {
            $validator->addRules($rules);
        }
    }

    /**
     * Get the rules from the used traits.
     *
     * @return array
     */
    protected function getTraitRules()
    {
        return array_reduce(class_uses(static::class), function ($rules, $trait) {
            $rulesMethod = $this->makeRulesMethodName($trait);

            if (! is_null($rulesMethod) && method_exists($this, $rulesMethod)) {
                $rules = array_merge($rules, $this->{$rulesMethod}());
            }

            return $rules;
        }, []);
    }

    /**
     * Make the rules method name based on the given trait name, if it matches the required format.
     *
     * @param  string  $trait
     * @return string
     */
    protected function makeRulesMethodName($trait)
    {
        preg_match('/^Has([A-Za-z]+)Fields$/', class_basename($trait), $matches);

        return isset($matches[1]) ? camel_case($matches[1]).'Rules' : null;
    }
}