It *is* optimized away (according to Deparse), but not before satisfying our needs. The safe version would be:

{
   use warnings;
   my $thingy = 'thangy';
   sub doit { no warnings 'void';
              $thingy;  # Close over $thingy
              eval 'print "thingy is $thingy\n"'; }
}

doit();  # "thingy is thangy"
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