From @ajs

In this code​:

sub infix​:<↑>($a, $b) is assoc<right> {$a ** $b}; sub infix​:<↑↑>($a, $b) is
assoc<right> { [↑] $a xx $b }; say 3↑↑3

The say produces the right answer (7625597484987) but it also produces this
warning​:

Useless use of $a in sink context (line 1)

It's not clear why this would be, since we are using both $a and $b in a
context that's very much not sunk... or so it would seem...

This result is on latest circa​:

This is Rakudo version 2016.07.1-79-gaa5e494 built on MoarVM version
2016.07-3-gc01472d
implementing Perl 6.c.

Under​:

Linux hostname 3.13.0-24-generic #​47-Ubuntu SMP Fri May 2 23​:30​:00 UTC 2014
x86_64 x86_64 x86_64 GNU/Linux

From IRC discussion​:

[15​:45] <harmil_wk> m​: sub infix​:<↑>($a, $b) is assoc<right> {$a ** $b};
sub infix​:<↑↑>($a, $b) is assoc<right> { [↑] $a xx $b }; sub
infix​:<↑↑↑>($a, $b) is assoc<right> { [↑↑] $a xx $b }; sub infix​:<↑↑↑↑>($a,
$b) is assoc<right> { [↑↑↑] $a xx $b }; say 3↑↑3
[15​:45] <+camelia> rakudo-moar aa5e49​: OUTPUT«WARNINGS for <tmp>​:␤Useless
use of $a in sink context (lines 1, 1, 1)␤7625597484987␤»
[15​:45] <harmil_wk> Am I missing something, there? Seems like there should
be no warning.
[15​:47] <unmatched}> bisect​: m​: sub infix​:<↑>($a, $b) is assoc<right> {$a
** $b}; sub infix​:<↑↑>($a, $b) is assoc<right> { [↑] $a xx $b }; sub
infix​:<↑↑↑>($a, $b) is assoc<right> { [↑↑] $a xx $b }; sub infix​:<↑↑↑↑>($a,
$b) is assoc<right> { [↑↑↑] $a xx $b }; say 3↑↑3
[15​:47] <[Coke]> it doesn't warn for me locally on 2016.07.1
[15​:48] <bisectable> unmatched}​: Exit code is 0 on both starting points,
bisecting by using the output
[15​:48] <bisectable> unmatched}​: bisect log​:
https://gist.github.com/369412d2b8ff352b2e8545b35f89846f
[15​:48] <bisectable> unmatched}​: (2016-07-26)
rakudo/rakudo@5334cb7
[15​:48] <unmatched}> harmil_wk​: would you please open a ticket for it?
[15​:48] <harmil_wk> Sure
[15​:48] <unmatched}> huggable​: rakudobug
[15​:48] <huggable> unmatched}, To report a bug, email detailed description
and any test cases to rakudobug@​perl.org or use perl6 query on
http://rt.perl.org ; see https://github.com/rakudo/rakudo/#reporting-bugs
[15​:49] <harmil_wk> I've been pretty prolific with the bug reports of late.
I'm worried I'm going on a list ;)
[15​:49] <unmatched}> :)
[15​:49] <[Coke]> harmil_wk​: you'll never catch up with masak, so dont'
worry. :)
[15​:50] <unmatched}> harmil_wk​: oh and would you include the link to the
commit that bisectable gave above?
[15​:50] <unmatched}> TimToady​: if you're around and have time, seems it
points to the sinkiness propagation​:
rakudo/rakudo@5334cb7
[15​:50] <[Coke]> unmatched}​: note that, in general, we want files attached
to tickets, not links to pastebots.
[15​:51] <[Coke]> but I realize that's a pita in general.
[15​:51] <unmatched}> [Coke]​: I mean the link to the commit

--
Aaron Sherman, M.​:
P​: 617-440-4332 Google Talk, Email and Google Plus​: ajs@​ajs.com
Toolsmith, developer, gamer and life-long student.

From @TimToady

The onearg form of reduce wasn't correctly marking wantedness of either the operator or the argument.

Fixed in fc28b67185d711cf8e4b3f9e6987e1ceee34e37b.

(We don't test sink warnings currenlty.)

@TimToady - Status changed from 'new' to 'resolved'

From @coke

Re-opening, marking testneeded.

--
Will "Coke" Coleda

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

From @LLFourn

test​:
Raku/roast@4fdee95

On Sat, Jul 30, 2016 at 5​:36 AM Will Coleda via RT <
bugs-comment@​bugs6.perl.org> wrote​:

Re-opening, marking testneeded.

--
Will "Coke" Coleda

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