Expected       Current
for (1..2) {
   for (1) {
      my $r = \$_;
      ++$$r;
      say $$r;         2 2            2 2   (threaded)
   }                                  [die] (non-threaded)
}

for (1..2) {
   for (1) {
      ++$_;
      say;             2 2            [die]
   }
}

for (1..2) {
   for (1..3) {
      ++$_;
      say;             234 234        234 345
   }
}
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