From @AlexDaniel

Differences between 2015.12 and HEAD​:

<AlexDaniel> committable6​: 2015.12,HEAD <a b c d b e>.first(‘b’|‘a’).say
<committable6> AlexDaniel, ¦«2015.12»​: aâ�¤¦«HEAD»​: any(b, a)

<AlexDaniel> committable6​: 2015.12,HEAD <a b c d b e>.first(‘b’|‘a’, :end).say
<committable6> AlexDaniel, ¦«2015.12»​: bâ�¤¦«HEAD»​: any(b, a)

In other words, .first used to return the first element even if you pass a junction as a parameter. Now it returns another junction.

Bisectable points to this commit​: rakudo/rakudo@157b46e

<timotimo> we're really hoping to use a matcher there, i think
<masak> .grep uses a matcher, and so .first ought to also

IRC discussion originates here​: http://irclog.perlgeek.de/perl6/2016-09-18#i_13233528
But useful comments start here​: http://irclog.perlgeek.de/perl6/2016-09-18#i_13233576

From @BenGoldberg1

Here is a snippet from #perl6 on freenode​:

<BenGoldberg> m​: ('a', 42, 'b', 22/7, 'c', 23).first(Int|Rat, :kv).say
<+camelia> rakudo-moar 641ee1​: OUTPUT«any((1 42), (3 3.142857))â�¤Â»

The result I expected was OUTPUT«(1 42)�»

The docs say that the first argument for .first is Mu $matcher, and therefor autothreading should not happen.

Rakudo implements .first using a couple of internal helper methods, !first-accepts and !first-accepts-end, located here​: https://github.com/rakudo/rakudo/blob/641ee1e/src/core/Any-iterable-methods.pm#L1185 and
https://github.com/rakudo/rakudo/blob/641ee1e/src/core/Any-iterable-methods.pm#L1201

Both of these helpers have a first argument of $test, which is untyped, and is therefor of type Any.

Because of this, when either of these helper methods is called with a Junction, autothreading occurs.

So, if you could add a couple of Mu�s, I�d appreciate it.

Thanks, Ben Goldberg

From @lizmat

This is a dup of #​129304, which has been fixed with c78f5dc7df5b1398d2867 , tests needed.

On 19 Sep 2016, at 01​:00, Benjamin Goldberg (via RT) <perl6-bugs-followup@​perl.org> wrote​:

# New Ticket Created by Benjamin Goldberg
# Please include the string​: [perl #​129305]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=129305 >

Here is a snippet from #perl6 on freenode​:

<BenGoldberg> m​: ('a', 42, 'b', 22/7, 'c', 23).first(Int|Rat, :kv).say
<+camelia> rakudo-moar 641ee1​: OUTPUT«any((1 42), (3 3.142857))â�¤Â»

The result I expected was OUTPUT«(1 42)�»

The docs say that the first argument for .first is Mu $matcher, and therefor autothreading should not happen.

Rakudo implements .first using a couple of internal helper methods, !first-accepts and !first-accepts-end, located here​: https://github.com/rakudo/rakudo/blob/641ee1e/src/core/Any-iterable-methods.pm#L1185 and
https://github.com/rakudo/rakudo/blob/641ee1e/src/core/Any-iterable-methods.pm#L1201

Both of these helpers have a first argument of $test, which is untyped, and is therefor of type Any.

Because of this, when either of these helper methods is called with a Junction, autothreading occurs.

So, if you could add a couple of Mu�s, I�d appreciate it.

Thanks, Ben Goldberg

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

From @zoffixznet

Tests added in Raku/roast@7cdeab4a68

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