Rector Rule to enable ImmutableDates in Laravel by updating the AppServiceProvider

UseCarbonImmutableInAppServiceProviderRector.php

<?php

namespace App\Rector;

use PhpParser\Node;
use PhpParser\Node\Expr\StaticCall;
use PhpParser\Node\Name\FullyQualified;
use PhpParser\Node\Stmt\ClassLike;
use PhpParser\Node\Stmt\ClassMethod;
use PhpParser\Node\Stmt\Expression;
use PHPStan\Type\ObjectType;
use Rector\Core\Rector\AbstractRector;
use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
use Illuminate\Support\Facades\Date;
use Carbon\CarbonImmutable;
use Illuminate\Support\ServiceProvider;

class UseCarbonImmutableInAppServiceProviderRector extends AbstractRector
{
    /**
     * @var string
     */
    private const BOOT = 'boot';

    public function getRuleDefinition(): RuleDefinition
    {
        return new RuleDefinition('Add Date::use(CarbonImmutable::class) to boot method of AppServiceProvider', [
            new CodeSample(<<<'CODE_SAMPLE'
    public function boot()
    {
        //
    }
CODE_SAMPLE, <<<'CODE_SAMPLE'
    public function boot()
    {
        Date::use(CarbonImmutable::class)
    }
CODE_SAMPLE
            ),
        ]);
    }

    /**
     * @inheritDoc
     */
    public function getNodeTypes(): array
    {
        return [ClassMethod::class];
    }

    /**
     * @param ClassMethod $node
     * @return Node|null
     */
    public function refactor(Node $node)
    {
        $classLike = $this->betterNodeFinder->findParentType($node, ClassLike::class);

        if (! $classLike instanceof ClassLike) {
            return null;
        }

        if (! $this->isObjectType($classLike, new ObjectType(ServiceProvider::class))) {
            return null;
        }

        if (! $this->isName($classLike->name, 'AppServiceProvider')) {
            return null;
        }

        if (! $this->isName($node->name, self::BOOT)) {
            return null;
        }


        $fullyQualifiedDateFacade = new FullyQualified(Date::class);
        $fullyQualifiedCarbonImmutable = new FullyQualified(CarbonImmutable::class);

        $argument = new Node\Arg(new Node\Scalar\String_($fullyQualifiedCarbonImmutable));

        $staticCall = new StaticCall($fullyQualifiedDateFacade, 'use', [$argument]);

        $parentStaticCallExpression = new Expression($staticCall);

        $node->stmts = array_merge([$parentStaticCallExpression], (array)$node->stmts);

        return $node;
    }
}

This rule was created during a late night coding session to learn Rector. It's probably easier to do this manually by reading Michael's guide: https://dyrynda.com.au/blog/laravel-immutable-dates