use strict;
use warnings;
use warnings::register;

use Symbol 'qualify_to_ref';

sub import {
  my $cur  = shift;
  my $dest = caller;

  for my $g (grep $cur->can($_),  @_) {
    warnings::warnif("sub '$g' already exists in $dest") and next
      if $dest->can($g);

    my($dest, $src) = map qualify_to_ref("$_\::$g"), $dest, $cur;
    *$dest = *$src;
  }
}