Final Class Yiisoft\Validator\Rule\EachHandler

                public function validate(mixed $value, RuleInterface $rule, ValidationContext $context): Result
{
    if (!$rule instanceof Each) {
        throw new UnexpectedRuleException(Each::class, $rule);
    }
    $value = $context->getParameter(ValidationContext::PARAMETER_VALUE_AS_ARRAY) ?? $value;
    if (!is_iterable($value)) {
        return (new Result())->addError($rule->getIncorrectInputMessage(), [
            'property' => $context->getTranslatedProperty(),
            'Property' => $context->getCapitalizedTranslatedProperty(),
            'type' => get_debug_type($value),
        ]);
    }
    $rules = $rule->getRules();
    $result = new Result();
    $originalEachKey = $context->getParameter(Each::PARAMETER_EACH_KEY);
    foreach ($value as $index => $item) {
        if (!is_int($index) && !is_string($index)) {
            return (new Result())->addError($rule->getIncorrectInputKeyMessage(), [
                'property' => $context->getTranslatedProperty(),
                'Property' => $context->getCapitalizedTranslatedProperty(),
                'type' => get_debug_type($index),
            ]);
        }
        $context->setParameter(Each::PARAMETER_EACH_KEY, $index);
        $itemResult = $context->validate($item, $rules);
        if ($itemResult->isValid()) {
            continue;
        }
        foreach ($itemResult->getErrors() as $error) {
            $result->addErrorWithoutPostProcessing(
                $error->getMessage(),
                $error->getParameters(),
                $error->getValuePath() === [] ? [$index] : [$index, ...$error->getValuePath()],
            );
        }
        if ($rule->stopOnError) {
            return $result;
        }
    }
    $context->setParameter(Each::PARAMETER_EACH_KEY, $originalEachKey);
    return $result;
}