Cross meta operator on empty list complains "This type (Scalar) does not support elems"

[p6rt]

Migrated from rt.perl.org#131395 (status was 'resolved')

Searchable as RT131395$

[p6rt]

From @thundergnat

Using a cross meta operator on an empty list complains "This type
(Scalar) does not support elems".

  say (1,2).elems; say ().elems; say (1,2) X ();

yields "2␤0␤This type (Scalar) does not support elems"

Seems to work correctly with arrays instead of lists.

  say [1,2].elems; say [].elems; say [1,2] X [];

Linux Mint 17.2

perl6 -v
This is Rakudo version 2017.05 built on MoarVM version 2017.05
implementing Perl 6.c.

[p6rt]

From @zoffixznet

https://irclog.perlgeek.de/perl6/2017-05-29#i_14654174

16​:54 bisectable6 MasterDuke, bisect log​: https://gist.github.com/7d49ce1401bee0ab3127c5d1be2a919e
16​:54 MasterDuke, (2017-01-16) rakudo/rakudo@8a3ff7b

16​:57 Zoffix m​: use nqp; nqp​::elems(nqp​::getattr((), List, '$!reified'))
16​:57 camelia rakudo-moar a18c06​: OUTPUT​: «This type (Scalar) does not support elems␤ in block <unit> at <tmp> line 1␤␤»

17​:00 m​: use nqp; dd nqp​::getattr((), List, '$!reified').^name; dd nqp​::getattr([], List, '$!reified').^name
17​:00 camelia rakudo-moar a18c06​: OUTPUT​: «"Mu"␤"IterationBuffer"␤»
17​:00 Zoffix Both prolly should be the same? So this bug doesn't occur elsewhere?

[p6rt]

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

[p6rt]

From @lizmat

On 29 May 2017, at 19​:06, Zoffix Znet via RT <perl6-bugs-followup@​perl.org> wrote​:

https://irclog.perlgeek.de/perl6/2017-05-29#i_14654174

16​:54 bisectable6 MasterDuke, bisect log​: https://gist.github.com/7d49ce1401bee0ab3127c5d1be2a919e
16​:54 MasterDuke, (2017-01-16) rakudo/rakudo@8a3ff7b

16​:57 Zoffix m​: use nqp; nqp​::elems(nqp​::getattr((), List, '$!reified'))
16​:57 camelia rakudo-moar a18c06​: OUTPUT​: «This type (Scalar) does not support elems␤ in block <unit> at <tmp> line 1␤␤»

17​:00 m​: use nqp; dd nqp​::getattr((), List, '$!reified').^name; dd nqp​::getattr([], List, '$!reified').^name
17​:00 camelia rakudo-moar a18c06​: OUTPUT​: «"Mu"␤"IterationBuffer"␤»
17​:00 Zoffix Both prolly should be the same? So this bug doesn't occur elsewhere?

FWIW, I’m testing a fix.

Liz

[p6rt]

From @zoffixznet

On Mon, 29 May 2017 10​:02​:27 -0700, thundergnat@​comcast.net wrote​:

Using a cross meta operator on an empty list complains "This type
(Scalar) does not support elems".

 say \(1,2\)\.elems; say \(\)\.elems; say \(1,2\) X \(\);

yields "2␤0␤This type (Scalar) does not support elems"

Seems to work correctly with arrays instead of lists.

     say \[1,2\]\.elems; say \[\]\.elems; say \[1,2\] X \[\];

Linux Mint 17.2

perl6 -v
This is Rakudo version 2017.05 built on MoarVM version 2017.05
implementing Perl 6.c.

Thank you for the report. lizmat++ fixed the issue.

Fix​: rakudo/rakudo@9494cbd
Test​: Raku/roast@0faf3c3

[p6rt]

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

[p6rt]

From @smls

On Mon, 29 May 2017 11​:36​:49 -0700, cpan@​zoffix.com wrote​:

On Mon, 29 May 2017 10​:02​:27 -0700, thundergnat@​comcast.net wrote​:

Using a cross meta operator on an empty list complains "This type
(Scalar) does not support elems".

 say \(1,2\)\.elems; say \(\)\.elems; say \(1,2\) X \(\);

yields "2␤0␤This type (Scalar) does not support elems"

Seems to work correctly with arrays instead of lists.

     say \[1,2\]\.elems; say \[\]\.elems; say \[1,2\] X \[\];

Linux Mint 17.2

perl6 -v
This is Rakudo version 2017.05 built on MoarVM version 2017.05
implementing Perl 6.c.

Thank you for the report. lizmat++ fixed the issue.

Fix​: rakudo/rakudo@9494cbd
Test​: Raku/roast@0faf3c3

Re-opening, because it hasn't been fixed for the Xop case yet​:

  ➜ say () X+ (1, 2);
  This type (Scalar) does not support elems

  ➜ say (1,2) X~ ();
  This type (Scalar) does not support elems

  ➜ say () X=> ();
  This type (Scalar) does not support elems

Bisectable¹ blames a commit² from January.

---

[1] https://gist.github.com/Whateverable/f1b3066f1e2c45df7ab5e0aa7aeee3a7
[2] rakudo/rakudo@a26f513

---

This is Rakudo version 2017.09-142-ga89add0bf built on MoarVM version 2017.09.1-49-gb3dd812a
implementing Perl 6.c.

[p6rt]

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

[p6rt]

From @dogbert17

On Sat, 30 Sep 2017 12​:40​:59 -0700, smls75@​gmail.com wrote​:

On Mon, 29 May 2017 11​:36​:49 -0700, cpan@​zoffix.com wrote​:

On Mon, 29 May 2017 10​:02​:27 -0700, thundergnat@​comcast.net wrote​:

Using a cross meta operator on an empty list complains "This type
(Scalar) does not support elems".

say (1,2).elems; say ().elems; say (1,2) X ();

yields "2␤0␤This type (Scalar) does not support elems"

Seems to work correctly with arrays instead of lists.

say [1,2].elems; say [].elems; say [1,2] X [];

Linux Mint 17.2

perl6 -v
This is Rakudo version 2017.05 built on MoarVM version 2017.05
implementing Perl 6.c.

Thank you for the report. lizmat++ fixed the issue.

Fix​: rakudo/rakudo@9494cbd
Test​: Raku/roast@0faf3c3

Re-opening, because it hasn't been fixed for the Xop case yet​:

➜ say () X+ (1, 2);
This type (Scalar) does not support elems

➜ say (1,2) X~ ();
This type (Scalar) does not support elems

➜ say () X=> ();
This type (Scalar) does not support elems

Bisectable¹ blames a commit² from January.

---
[1]
https://gist.github.com/Whateverable/f1b3066f1e2c45df7ab5e0aa7aeee3a7
[2] rakudo/rakudo@a26f513

---
This is Rakudo version 2017.09-142-ga89add0bf built on MoarVM version
2017.09.1-49-gb3dd812a
implementing Perl 6.c.

Fixed with commit rakudo/rakudo@6c93fde
Roast tests added with Raku/roast@7d47580

Closing

[p6rt]

@dogbert17 - Status changed from 'open' to 'resolved'