use strict;
use Scalar::Util qw(weaken isweak);

my $a = 1;

my $r1 = *main::a{SCALAR};
my $r2 = *main::a{SCALAR};

weaken $r1;

print "r1 is weak\n" if isweak $r1;
print "r2 is weak\n" if isweak $r2;