If I set the global variable http_proxy_port to 3142 and use it in the following puppet code:

  class { 'apt':
    proxy => {
      host => $http_proxy,
      port => 3142, # XXX $http_proxy_port,
      ensure => present,
    }
  }                                                                                                                                                                                    

I get this error: Server Error: Evaluation Error: Error while evaluating a Function Call, assert_type(): expects an Integer value, got String at /etc/puppetlabs/code/modules/apt/manifests/init.pp:75:5 on node

I would like to be able to set the type for global variables. Just like with smart class variables.