If you wanted to use a hash variable as an alias to the original hash, it would go like this:

use strict;
use warnings;

my %foo = ( a => 1, b => 2, c => 3 );

mysub(\%foo);

sub mysub {
  our (%x);
  local *x = shift;

  foreach ( sort keys %x ) {
    print "$_ -> $x{$_}\n";
  }
}
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