From @masak

In Rakudo 7ef386​:

$ perl6 -e 'class A {}; say (A.new, A.new).sort'
Multiple Dispatch​: No suitable candidate found for 'cmp', with signature 'PP->I'
[...]

$ perl6 -e 'class A {}; multi sub cmp(A $a, A $b) { 1 }; say (A.new,
A.new).sort'
Multiple Dispatch​: No suitable candidate found for 'cmp', with signature 'PP->I'
[...]

I'm not sure the end user should ever see that ungainly
error-with-Parrot-signature. It's also unfortunate that there doesn't
seem to be a way to make it go away for user-defined classes.

From @bbkr

[18​:12] <bbkr> rakudo​: class A {}; say (A.new, A.new).sort # is this
correct output?
[18​:12] <p6eval> rakudo 9808d7​: OUTPUT«A()<0x82b09f0>A()<0x82b1170>␤»
[18​:13] --> eternaleye has joined this channel
(~quassel@​unaffiliated/eternaleye).
[18​:13] <masak> bbkr​: what would you expect it to sort on?
[18​:14] <PerlJam> bbkr​: it looks correct to me 0x82b09f0 comes before
0x82b1170 :)
[18​:15] <bbkr> masak​: IMO this is correct - sort used "~A.new" output,
but I want to be sure before taking
http://rt.perl.org/rt3/Ticket/Display.html?id=71258 for tests
[18​:15] <masak> bbkr​: looking.
[18​:16] <masak> bbkr​: the ticket has two parts. the above shows that the
first part is fixed.
[18​:16] --> justatheory has joined this channel
(~justatheo@​c-24-21-193-250.hsd1.or.comcast.net).
[18​:17] <bbkr> masak​: second part works also
[18​:17] <bbkr> rakudo​:
[18​:17] <bbkr> class A {}; multi sub cmp(A $a, A $b) { 1 }; say (A.new,
[18​:17] <bbkr> A.new).sort
[18​:17] <p6eval> rakudo 9808d7​: ( no output )
[18​:17] <bbkr> rakudo​: class A {}; multi sub cmp(A $a, A $b) { 1 }; say
(A.new, A.new).sort
[18​:17] <p6eval> rakudo 9808d7​: OUTPUT«A()<0x69f1460>A()<0x6a1d7a0>␤»
[18​:19] <masak> rakudo​: class A { has $.x }; multi sub cmp(A $a, A $b) {
$a.x <=> $b.x }; say (A.new(​:x(2)), A.new(​:x(3)), A.new(​:x(1))).sort
[18​:19] <p6eval> rakudo 9808d7​:
OUTPUT«A()<0x73823e0>A()<0x7384300>A()<0x73861e0>␤»
[18​:19] <masak> er :)
[18​:19] <masak> rakudo​: class A { has $.x; method Str { $.x } }; multi
sub cmp(A $a, A $b) { $a.x <=> $b.x }; say (A.new(​:x(2)), A.new(​:x(3)),
A.new(​:x(1))).sort
[18​:19] <p6eval> rakudo 9808d7​: OUTPUT«123␤»
[18​:19] <masak> \o/
[18​:20] <masak> bbkr​: yes. it should be taken for tests.
[18​:20] <pugssvn> r31847 | Kodi++ | [t/spec] Fixed some Instant and
Duration tests and fudged some for Rakudo.
[18​:21] <bbkr> BTW​: how to get class instance memory address that can be
assigned to variable?
[18​:21] <jnthn> .WHERE
[18​:21] <bbkr> rakudo​: class A{}; A.new.WHERE.say
[18​:21] <p6eval> rakudo 9808d7​: OUTPUT«130402704␤»
[18​:22] <bbkr> jnthn​: thanks!

taken for tests

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

From @bbkr

rechecked on * release, also works

tests in
t/spec/S32-list/sort.t

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

From @kyleha

This is an automatically generated mail to inform you that tests are now available in t/spec/S32-list/sort.t

commit 307c1ab2718b1bb94c287d2b3ce1c365753f362a
Author​: bbkr <bbkr@​c213334d-75ef-0310-aa23-eaa082d1ae64>
Date​: Fri Jul 30 16​:57​:13 2010 +0000

  [t/spec] tests for RT #​71258 Cant sort objects of a custom class, cant supply .cmp method in Rakudo
 
  git-svn-id​: http://svn.pugscode.org/pugs@&#8203;31870 c213334d-75ef-0310-aa23-eaa082d1ae64

diff --git a/t/spec/S32-list/sort.t b/t/spec/S32-list/sort.t
index 1e0d219..27205a2 100644
--- a/t/spec/S32-list/sort.t
+++ b/t/spec/S32-list/sort.t
@@ -1,6 +1,6 @@
 use v6;
 use Test;
-plan 31;
+plan 35;
 
 # L<S32::Containers/"List"/"=item sort">
 
@@ -220,4 +220,37 @@ plan 31;
         'sort accepts rand method';
 }
 
+# RT #71258
+{
+    class RT71258_1 { };
+
+    my @sorted;
+
+    lives_ok { @sorted = (RT71258_1.new, RT71258_1.new).sort },
+        'sorting by stringified class instance (name and memory address)';
+
+    ok ([<]@sorted.map({.WHERE})),
+        'checking sort order by class memory address';
+
+    class RT71258_2 {
+        has $.x;
+        method Str { $.x }
+    };
+
+    multi sub cmp(RT71258_2 $a, RT71258_2 $b) {
+        $a.x <=> $b.x;
+    }
+
+    lives_ok {
+        @sorted = (
+            RT71258_2.new(x => 2),
+            RT71258_2.new(x => 3),
+            RT71258_2.new(x => 1)
+        ).sort
+    }, 'sorting stringified class instance with custom cmp';
+
+    is ~@sorted, '1 2 3',
+        'checking sort order with custom cmp';
+}
+
 # vim: ft=perl6