src/Symfony/Component/DependencyInjection/Container.php
public function normalizeId($id)
    {
        if (!\is_string($id)) {
            $id = (string) $id;
        }
        if (isset($this->normalizedIds[$normalizedId = strtolower($id)])) {
            $normalizedId = $this->normalizedIds[$normalizedId];
            if ($id !== $normalizedId) {
                @trigger_error(sprintf('Service identifiers will be made case sensitive in Symfony 4.0. Using "%s" instead of "%s" is deprecated since Symfony 3.3.', $id, $normalizedId), E_USER_DEPRECATED);
            }
        } else {
            $normalizedId = $this->normalizedIds[$normalizedId] = $id;
        }

        return $normalizedId;
    }
public function normalizeId($id)
    {
        if (!\is_string($id)) {
            $id = (string) $id;
        }
        if (isset($this->normalizedIds[$normalizedId = strtolower($id)])) {
            $normalizedId = $this->normalizedIds[$normalizedId];
            if ($id !== $normalizedId) {
                @trigger_error(sprintf('Service identifiers will be made case sensitive in Symfony 4.0. Using "%s" instead of "%s" is deprecated since Symfony 3.3.', $id, $normalizedId), E_USER_DEPRECATED);
            }
        } else {
            $normalizedId = $this->normalizedIds[$normalizedId] = $id;
        }

        return $normalizedId;
    }
public function normalizeId ( $ id ) { if ( ! \ is_string ( $ id ) ) { $ id = ( string ) $ id ; } if ( isset ( $ this -> normalizedIds [ $ normalizedId = strtolower ( $ id ) ] ) ) { $ normalizedId = $ this -> normalizedIds [ $ normalizedId ] ; if ( $ id !== $ normalizedId ) { @ trigger_error ( sprintf ( 'Service identifiers will be made case sensitive in Symfony 4.0. Using "%s" instead of "%s" is deprecated since Symfony 3.3.' , $ id , $ normalizedId ) , E_USER_DEPRECATED ) ; } } else { $ normalizedId = $ this -> normalizedIds [ $ normalizedId ] = $ id ; } return $ normalizedId ; }
Returns the case sensitive id used at registration time.

@param string $id

@return string

@internal
Returns the case sensitive id used at registration time .