ArrayUnpackingRule.php

<?php declare(strict_types = 1);

namespace PHPStan\Rules\Arrays;

use PhpParser\Node;
use PhpParser\Node\Expr\ArrayItem;
use PHPStan\Analyser\Scope;
use PHPStan\Php\PhpVersion;
use PHPStan\Rules\Rule;
use PHPStan\Rules\RuleErrorBuilder;
use PHPStan\Type\StringType;

/**
 * @implements Rule<ArrayItem>
 */
class ArrayUnpackingRule implements Rule
{

	private PhpVersion $phpVersion;

	public function __construct(PhpVersion $phpVersion)
	{
		$this->phpVersion = $phpVersion;
	}

	public function getNodeType(): string
	{
		return ArrayItem::class;
	}

	public function processNode(Node $node, Scope $scope): array
	{
		if ($node->unpack === false || $this->phpVersion->supportsArrayUnpackingWithStringKeys()) {
			return [];
		}

		$valueType = $scope->getType($node->value);

		if ((new StringType())->isSuperTypeOf($valueType->getIterableKeyType())->no()) {
			return [];
		}

		return [RuleErrorBuilder::message('Array unpacking cannot be used on array that potentially has string keys.')->build()];
	}

}