From @masak

<masak> rakudo​: my ($a is readonly) = 5; say $a; $a = 42; say $a
<p6eval> rakudo 79d0b9​: OUTPUT«5␤42␤»
<PerlJam> heh
* masak submits rakudobug
<masak> which behaviour do I expect? is the 5 assignment allowed?
<masak> probably not, right?
<TimToady> allowed
<masak> ok.
<TimToady> assignment semantic analyzer always has to look at left
side to see if a declarator governs semantics
<PerlJam> surely the assignment must be allowed. How do you get a
value otherwise?
<masak> PerlJam​: my ($a is readonly = 5)
<TimToady> (my $a is readonly) = 5 would not be allowed
<TimToady> well, probably not
<masak> ok, so _not_ allowed... :)
<PerlJam> masak​: well, there's 3 different initialization forms we
just talked about. Which are you referring to? :)
<TimToady> only my form is disallowed
<TimToady> er
<TimToady> the form I said
<PerlJam> heh
<masak> PerlJam​: the one TimToady just disallowed.
<TimToady> it's like difference between state $x = 0 and (state $x) = 0
<masak> everything you say will be used against you in the bug report :)
<PerlJam> my ($a is readonly, $b is readonly = 5) = 6; # does this work?
<PerlJam> ($a = 6 and $b = 5)
<masak> PerlJam​: not if the '(my $a is readonly) = 5' doesn't work.
<masak> PerlJam​: seems like the same situation with your $a.
<TimToady> no, it's not
<masak> :)
<TimToady> the my is outside
<TimToady> (my vs my (
<masak> oh!
<masak> I missed that!
<masak> important distinction...
<TimToady> I've been saying nothing else for a month
* PerlJam gets masak some TimToady specs
<TimToady> well, a minute, anyway
<masak> sorry, I should pay more attention... :P
<masak> oh, ok. I see now.
<masak> there's no way I can explain this in the bug report save for
quoting the whole thing, misunderstanding and all. :)
<TimToady> consider it an exercise in integrity :)
* masak does that
<masak> rakudo​: (my $a is readonly) = 5; say $a
<p6eval> rakudo 79d0b9​: OUTPUT«5␤»

From @kyleha

This is an automatically generated mail to inform you that tests are now available in t/spec/S06-traits/is-readonly.t

commit 60eb8fe4fe2597318596142bd3268ad9d4b49033
Author​: kyle <kyle@​c213334d-75ef-0310-aa23-eaa082d1ae64>
Date​: Tue Oct 27 02​:34​:58 2009 +0000

  [t/spec] Test for RT #​65900
 
  git-svn-id​: http://svn.pugscode.org/pugs@&#8203;28913 c213334d-75ef-0310-aa23-eaa082d1ae64

diff --git a/t/spec/S06-traits/is-readonly.t b/t/spec/S06-traits/is-readonly.t
index 0774abd..389f8a7 100644
--- a/t/spec/S06-traits/is-readonly.t
+++ b/t/spec/S06-traits/is-readonly.t
@@ -4,7 +4,7 @@ use Test;
 # L<S06/"Parameter traits"/"=item is readonly">
 # should be moved with other subroutine tests?
 
-plan 9;
+plan *;
 
 {
     my $a is readonly := 42;
@@ -40,4 +40,16 @@ plan 9;
     ok (try { VAR($a).defined }), ".VAR on a plain normal initialized variable returns true";
 }
 
+# RT #65900
+{
+    my ($rt65900 is readonly) = 5;
+    is $rt65900, 5, 'my ($x is readonly) can take assignment';
+    dies_ok { $rt65900 = 'ro' }, 'dies on assignment to readonly variable';
+
+    dies_ok { (my $rt65900 is readonly) = 5 },
+        'dies on assignment to (my $x is readonly)';
+}
+
+done_testing;
+
 # vim: ft=perl6

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

From @bbkr

$ perl6 -e 'my ($a is readonly) = 5; say $a; $a = 42; say $a'
Cannot assign to readonly value
  in '&infix​:<=>' at line 1
  in main program body at line 1

So it dies properly now.

But test file is not working due to := not implemented in earlier tests.

From @coke

On Wed Jun 30 07​:14​:21 2010, bbkr wrote​:

$ perl6 -e 'my ($a is readonly) = 5; say $a; $a = 42; say $a'
Cannot assign to readonly value
in '&infix​:<=>' at line 1
in main program body at line 1

So it dies properly now.

But test file is not working due to := not implemented in earlier
tests.

Good news​: fudged the test and added it to t/spectest.data so it's run.

Bad news​: I had to fudge these tests too.

--
Will "Coke" Coleda

From @usev6

Things have changed and infix​:<​::=> is used instead of a variable trait "is readonly". The tests for this ticket are gone with this commit​: Raku/roast@253242f

my $a is readonly = 5; say $a;
===SORRY!=== Error while compiling
Can't use unknown trait 'is readonly' in a variable declaration.
at :1
------> my $a is readonly ⏏= 5; say $a;
  expecting any of​:
  TypeObject
  default
  dynamic

(my $a is readonly) = 5; say $a;
Can't use unknown trait 'is readonly' in a variable declaration.
at :1
------> (my $a is readonly⏏) = 5; say $a;
  expecting any of​:
  TypeObject
  default
  dynamic

my ($a is readonly) = 5; say $a; $a++; say $a;
5
6

I think the last one should also result in a compile time error. But I don't know how to fix it.

From @usev6

On Wed Oct 01 13​:03​:29 2014, bartolin@​gmx.de wrote​:

my ($a is readonly) = 5; say $a; $a++; say $a;
5
6

I think the last one should also result in a compile time error. But I
don't know how to fix it.

AFAIU this doesn't die because '($a is readonly)' is parsed as a signature and is not checked as strictly as the assignments (see e.g. https://rt-archive.perl.org/perl6/Ticket/Display.html?id=74664#txn-686876).

So, we're back to 'things have changed and infix​:<​::=> is used instead of a variable trait "is readonly"'. To be sure that the right exception is thrown when someone uses the old "is readonly", I added two tests to S03-binding/ro.t with commit Raku/roast@8a07d59e32.

If I'm not mistaken, there is nothing else to do in this context. If that's not the case, please reopen the ticket.

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