CastStringHandler.php

<?php declare(strict_types = 1);

namespace PHPStan\Analyser\ExprHandler;

use PhpParser\Node\Expr;
use PhpParser\Node\Expr\Cast;
use PhpParser\Node\Identifier;
use PhpParser\Node\Stmt;
use PHPStan\Analyser\ExpressionContext;
use PHPStan\Analyser\ExpressionResult;
use PHPStan\Analyser\ExpressionResultStorage;
use PHPStan\Analyser\ExprHandler;
use PHPStan\Analyser\ExprHandler\Helper\MethodThrowPointHelper;
use PHPStan\Analyser\ImpurePoint;
use PHPStan\Analyser\MutatingScope;
use PHPStan\Analyser\NodeScopeResolver;
use PHPStan\DependencyInjection\AutowiredService;
use PHPStan\Php\PhpVersion;
use PHPStan\Reflection\InitializerExprTypeResolver;
use PHPStan\Type\Type;
use function sprintf;

/**
 * @implements ExprHandler<Cast\String_>
 */
#[AutowiredService]
final class CastStringHandler implements ExprHandler
{

	public function __construct(
		private InitializerExprTypeResolver $initializerExprTypeResolver,
		private PhpVersion $phpVersion,
		private MethodThrowPointHelper $methodThrowPointHelper,
	)
	{
	}

	public function supports(Expr $expr): bool
	{
		return $expr instanceof Cast\String_;
	}

	public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Expr $expr, MutatingScope $scope, ExpressionResultStorage $storage, callable $nodeCallback, ExpressionContext $context): ExpressionResult
	{
		$exprResult = $nodeScopeResolver->processExprNode($stmt, $expr->expr, $scope, $storage, $nodeCallback, $context->enterDeep());
		$impurePoints = $exprResult->getImpurePoints();
		$throwPoints = $exprResult->getThrowPoints();

		$exprType = $scope->getType($expr->expr);
		$toStringMethod = $scope->getMethodReflection($exprType, '__toString');
		if ($toStringMethod !== null) {
			if (!$toStringMethod->hasSideEffects()->no()) {
				$impurePoints[] = new ImpurePoint(
					$scope,
					$expr,
					'methodCall',
					sprintf('call to method %s::%s()', $toStringMethod->getDeclaringClass()->getDisplayName(), $toStringMethod->getName()),
					$toStringMethod->isPure()->no(),
				);
			}

			if ($this->phpVersion->throwsOnStringCast()) {
				$throwPoint = $this->methodThrowPointHelper->getThrowPoint(
					$toStringMethod,
					$toStringMethod->getOnlyVariant(),
					new Expr\MethodCall($expr->expr, new Identifier('__toString')),
					$scope
				);
				if ($throwPoint !== null) {
					$throwPoints[] = $throwPoint;
				}
			}
		}

		$scope = $exprResult->getScope();

		return new ExpressionResult(
			$scope,
			hasYield: $exprResult->hasYield(),
			isAlwaysTerminating: $exprResult->isAlwaysTerminating(),
			throwPoints: $throwPoints,
			impurePoints: $impurePoints,
			truthyScopeCallback: static fn (): MutatingScope => $scope->filterByTruthyValue($expr),
			falseyScopeCallback: static fn (): MutatingScope => $scope->filterByFalseyValue($expr),
		);
	}

	public function resolveType(MutatingScope $scope, Expr $expr): Type
	{
		return $this->initializerExprTypeResolver->getCastType($expr, static fn (Expr $expr): Type => $scope->getType($expr));
	}

}