private function computeReflections(string $filename) : array
    {
        $singleFileSourceLocator = new SingleFileSourceLocator($filename, $this->astLocator);
        $reflector               = new ClassReflector(new AggregateSourceLocator([$singleFileSourceLocator, $this->sourceLocator]));

        return array_merge(
            $singleFileSourceLocator->locateIdentifiersByType($reflector, new IdentifierType(IdentifierType::IDENTIFIER_CLASS)),
            $singleFileSourceLocator->locateIdentifiersByType($reflector, new IdentifierType(IdentifierType::IDENTIFIER_FUNCTION))
        );
    }