protected function cacheMarkers(string $marker): void
    {
        $this->marked[$marker] = [];
        
        foreach ($this->definitions as $definition) {
            foreach ((array) $definition->markers as $m) {
                if ($m instanceof $marker) {
                    $this->marked[$marker][] = [
                        $definition,
                        $m
                    ];
                }
            }
        }
    }