rector/rules/Php74/NodeAnalyzer/ClosureArrowFunctionAnalyzer.php

<?php

declare(strict_types=1);

namespace Rector\Php74\NodeAnalyzer;

use PhpParser\Node;
use PhpParser\Node\Expr;
use PhpParser\Node\Expr\Closure;
use PhpParser\Node\Expr\ClosureUse;
use PhpParser\Node\Expr\Variable;
use PhpParser\Node\Stmt\Return_;
use Rector\Core\PhpParser\Comparing\NodeComparator;
use Rector\Core\PhpParser\Node\BetterNodeFinder;

final class ClosureArrowFunctionAnalyzer
{
    /**
     * @var BetterNodeFinder
     */
    private $betterNodeFinder;

    /**
     * @var NodeComparator
     */
    private $nodeComparator;

    public function __construct(BetterNodeFinder $betterNodeFinder, NodeComparator $nodeComparator)
    {
        $this->betterNodeFinder = $betterNodeFinder;
        $this->nodeComparator = $nodeComparator;
    }

    public function matchArrowFunctionExpr(Closure $closure): ?Expr
    {
        if (count($closure->stmts) !== 1) {
            return null;
        }

        $onlyStmt = $closure->stmts[0];
        if (! $onlyStmt instanceof Return_) {
            return null;
        }

        /** @var Return_ $return */
        $return = $onlyStmt;
        if ($return->expr === null) {
            return null;
        }

        if ($this->shouldSkipForUsedReferencedValue($closure, $return->expr)) {
            return null;
        }

        return $return->expr;
    }

    private function shouldSkipForUsedReferencedValue(Closure $closure, Expr $expr): bool
    {
        $referencedValues = $this->resolveReferencedUseVariablesFromClosure($closure);
        if ($referencedValues === []) {
            return false;
        }

        return (bool) $this->betterNodeFinder->findFirst([$expr], function (Node $node) use (
            $referencedValues
        ): bool {
            foreach ($referencedValues as $referencedValue) {
                if ($this->nodeComparator->areNodesEqual($node, $referencedValue)) {
                    return true;
                }
            }

            return false;
        });
    }

    /**
     * @return Variable[]
     */
    private function resolveReferencedUseVariablesFromClosure(Closure $closure): array
    {
        $referencedValues = [];

        /** @var ClosureUse $use */
        foreach ($closure->uses as $use) {
            if ($use->byRef) {
                $referencedValues[] = $use->var;
            }
        }

        return $referencedValues;
    }
}