.param not firing when matching on a nested middleware

[santialbo]

The following could be intentional behaviour but I'd like to confirm. Here's my usecase:

let router = new Router();
router
  .param('id', function*(id, next) {
    //do something
  })
  // some routes
  .use('/:id/children', children.routes())

Currently the param function doesn't fire when some url in the children router is matched. Is this a bug?