Some sort of a scoping bug when variables are used inside a closure in a &sub.wrap call in Rakudo

[p6rt]

Migrated from rt.perl.org#69312 (status was 'resolved')

Searchable as RT69312$

[p6rt]

From @masak

<masak> rakudo​: sub foo { say "=" x 40 }; for reverse ^40 -> $n {
&foo.wrap({ say "=" x $n; callsame; say "=" x $n }); }; foo
<p6eval> rakudo 0eaf62​:
  OUTPUT«␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤========================================␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤»
<masak> in the above code, why doesn't $n bind like I think it should?
<masak> I had hoped it would produce a nice triangle of ='s.
<pmurias> rakudo​: sub foo { say 40 }; for reverse ^40 -> $n { say
$n;&foo.wrap({ say
  $n; callsame; say $n }); }; foo
<p6eval> rakudo 0eaf62​:
  OUTPUT«39␤38␤37␤36␤35␤34␤33␤32␤31␤30␤29␤28␤27␤26␤25␤24␤23␤22␤21␤20␤19␤18␤17␤16␤15␤14␤13␤12␤11␤10␤9␤8␤7␤6␤5␤4␤3␤2␤1␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤40␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0
<pmurias> masak​: looks like some sort of a scoping bug
* masak submits rakudobug

I'm not certain this is a bug. But if Perl 6 doesn't conform to my
expectations in the above case, it'll be interesting to learn why not.

[p6rt]

From @jnthn

On Wed Sep 23 03​:14​:06 2009, masak wrote​:

<masak> rakudo​: sub foo { say "=" x 40 }; for reverse ^40 -> $n {
&foo.wrap({ say "=" x $n; callsame; say "=" x $n }); }; foo
<p6eval> rakudo 0eaf62​:

OUTPUT«␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤========================================␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤␤»

<masak> in the above code, why doesn't $n bind like I think it should?
<masak> I had hoped it would produce a nice triangle of ='s.
<pmurias> rakudo​: sub foo { say 40 }; for reverse ^40 -> $n { say
$n;&foo.wrap({ say
$n; callsame; say $n }); }; foo
<p6eval> rakudo 0eaf62​:

OUTPUT«39␤38␤37␤36␤35␤34␤33␤32␤31␤30␤29␤28␤27␤26␤25␤24␤23␤22␤21␤20␤19␤18␤17␤16␤15␤14␤13␤12␤11␤10␤9␤8␤7␤6␤5␤4␤3␤2␤1␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤40␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0␤0

<pmurias> masak​: looks like some sort of a scoping bug
* masak submits rakudobug

I'm not certain this is a bug. But if Perl 6 doesn't conform to my
expectations in the above case, it'll be interesting to learn why not.

Now it makes you a nice triangle​:

sub foo { say "=" x 40 }; for reverse ^40 -> $n { &foo.wrap({ say "="
x $n; callsame; say "=" x $n }); }; foo

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Tagging as "testneeded".

/jnthn

[p6rt]

The RT System itself - Status changed from 'new' to 'open'

[p6rt]

From @moritz

Now tested in S06-advanced/wrap.t

[p6rt]

@moritz - Status changed from 'open' to 'resolved'