From @masak

<felher> After i had a problem with a program i golfed down the issue
for quite some time. But i don't get why the two golfed-down
one-liners produce different output​:
<felher> nom​: my $x; my @​a = 1,2; $x = Array.new(@​a) => 'x';
$x.key[0]; @​a.pop(); say $x;
<p6eval> rakudo bd6742​: OUTPUT«[1, 2] => "x"␤»
<felher> nom​: my $x; my @​a = 1,2; $x = Array.new(@​a) => 'x'; @​a.pop(); say $x;
<p6eval> rakudo bd6742​: OUTPUT«[1] => "x"␤»
<felher> Might this be a bug?
<moritz> the difference is just the $x.key[0]; in sink context, right?
<felher> moritz​: yes
<moritz> probably is a bug, yes
<felher> Ah, okay. This was quite funny to debug, since everytime i
added debugging-output everything worked (because i printed it). And
everytime i deleted the print statements for debugging it failed again
:)
<masak> felher++ # nice golf!
<masak> felher​: should I submit it?
<felher> masak​: sure. Press your "masak submits rakudobug"-Button.
* masak submits rakudobug
<felher> masak​: you do have that button, don't you?
* masak smiles mysteriously
< felher> :D
<moritz> nom​: my @​a = 1,2; my $x = @​a => 'x'; @​a.pop(); say $x;
<p6eval> rakudo bd6742​: OUTPUT«[1] => "x"␤»
<masak> nom​: my @​a = 1,2; my $x = @​a => 'x'; $x.key[0]; @​a.pop(); say $x;
<p6eval> rakudo bd6742​: OUTPUT«[1] => "x"␤»
<masak> so Array.new is a necessary component of it all.
<masak> so Array.new is a necessary component of it all.
<jnthn> ah
<jnthn> I guess Array.new probably ain't exercised a great deal
<moritz> aye

From @usev6

This bug is still present. I added a test (fudged 'todo') to S32-array/pop.t with commit Raku/roast@046ad7e7e4

@usev6 - Status changed from 'new' to 'open'

From @usev6

Post-GLR the read operation with $x.key[0] isn't necessary to get the buggy behaviour​:

< bartolin> m​: my $x; my @​a = 1,2; $x = Array.new(@​a) => 'x'; @​a.pop(); say $x; # is that change with glr known/wanted
<+camelia> rakudo-moar e6f360​: OUTPUT«1 => x␤»
< GLRelia> rakudo-moar a6bb0b​: OUTPUT«[1 2] => x␤»
< bartolin> m​: my $x; my @​a = 1,2; $x = @​a => 'x'; @​a.pop(); say $x;
<+camelia> rakudo-moar e6f360​: OUTPUT«1 => x␤»
< GLRelia> rakudo-moar a6bb0b​: OUTPUT«[1] => x␤»

From @niner

The current behavior is correct due to the one item rule. Array.new(@​a) essentially creates a copy of @​a. Thus changing @​a will not affect the new array.

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