public function unsetParameterForConstructor($instanceName, $index) {
		if (isset($this->declaredInstances[$instanceName]['constructor'])) {
			$max = count($this->declaredInstances[$instanceName]['constructor']);
			if($index != $max - 1) {
				// It is forbidden to unset a parameter that is not the last.
				// Let set null
				$this->setParameterViaConstructor($instanceName, $index, null, 'primitive');
			}
			else {
				unset($this->declaredInstances[$instanceName]['constructor'][$index]);
			}
		}
	}