Hello perlboy_emeritus,

to be more explicit in this issue, I do not only think it's a bug, I am absolutely convinced it is. Some remarks:

• Having a workaround for a bug does in no way mean it is not a bug.
• Using $& in this scenario is dangerous, as it is affected by the very same bug. See extended example below.
• I cannot find anything in your code that would trigger the bug. This is fine and TIMTOWTDI
• perlop is very precise in The empty pattern "//:

  If the *PATTERN* evaluates to the empty string, the last *successfully* matched regular expression is used instead. (...) If no match has previously succeeded, this will (silently) act instead as a genuine empty pattern (which will always match). (...)

  As you can see from my example, // does not behave as described if there was a successful match and there happens a jump out of an inner block where // was applied. This clears $& and resets // to the genuine empty pattern.

#!/usr/bin/perl

use v5.24;
use warnings;

for my $label ('inner', 'outer') {
    say "goto $label";
    for ('c' .. 'g') {
        say "loop: $_";
        say "/d/ matched" if /d/;
        say "\$&: '$&'" if defined $&;
        {
            goto $label unless //;
            say "// matched";
            inner:
        }
        outer:
    }
    say '';
}
__DATA__
goto inner
loop: c
// matched
loop: d
/d/ matched
$&: 'd'
// matched
loop: e
$&: 'd'
loop: f
$&: 'd'
loop: g
$&: 'd'

goto outer
loop: c
// matched
loop: d
/d/ matched
$&: 'd'
// matched
loop: e
$&: 'd'
loop: f
// matched
loop: g
// matched
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