Cunstructor invocation failed using ReflectionClass in php

Following code was working earlier but now it's throwing error constructor invocation of class xyz failed:

code:

  $args = func_get_args();

  $obj = new ReflectionClass( 'xyz' );

  $instance = $obj->newInstanceArgs( $args );

Constructor:

public function __construct( SPImexCtrl &$proxy )
 {
  $this->proxy = &$proxy;
 }

My PHP Version: 5.6