Multiple "our" declarations in the same lexical scope are
   allowed if they are in different packages.  If they happened to
   be in the same package, Perl will emit warnings if you have
   asked for them.

       use warnings;
       package Foo;
       our $bar;       # declares $Foo::bar for rest of lexical scope
       $bar = 20;

       package Bar;
       our $bar = 30;  # declares $Bar::bar for rest of lexical scope
       print $bar;     # prints 30

       our $bar;       # emits warning