Custom Validation Rules don't work when used with multiple built-in rules

[apasov]

• Laravel Version: 5.6.14
• PHP Version: 7.2.3
• Database Driver & Version: MariaDB 10.2.14

Description:

It only works when combined with single built-in rule. Trying to use chained rules throws an error.

Steps To Reproduce:

This works:

$request->validate([
    'name' => 'string|max:255',
]);

And this works as well:

use App\Rules\CustomValidationRule;

$request->validate([
    'name' => ['string', new CustomValidationRule],
]);

But this fails:

use App\Rules\CustomValidationRule;

$request->validate([
    'name' => ['string|max:255', new CustomValidationRule],
]);

and throws an error:

message: Method Illuminate\Validation\Validator::validateString|max does not exist.
exception: BadMethodCallException
file: vendor/laravel/framework/src/Illuminate/Validation/Validator.php
line: 1146

You should use the built-in rules as separate strings:

'name' => ['string','max:255', new CustomValidationRule],

[apasov]

Thanks @GeraldPK
I think this should be mentioned in the docs so I proposed a PR.