use warnings;
use strict;

our $FH = "Hello, World!";
sub FH::awesome { print "<$FH>\n" }

FH->awesome;

open local *FH, "<", \my $x or die $!;

FH::awesome;
# => Use of uninitialized value $FH in concatenation (.) or string

FH->awesome;
# => Can't locate object method "awesome" via package "IO::File"