tina@lugosi:~$ perl -Mstrict -wle'
sub handler {
  our $x = 23;
  sub inner {
      print "inner before: $x";
      $x = $x + 42;
      print "inner: $x";
  }
}
inner();
'
Use of uninitialized value in concatenation (.) or string at -e line 5.
inner before: 
Use of uninitialized value in addition (+) at -e line 5.
inner: 42