From @LLFourn

role Foo {
  sub foo { };
  BEGIN &foo.wrap(-> {});
}

From @LLFourn

should have mentioned, this is the error msg​:

===SORRY!=== Error while compiling
  Cannot invoke this object

On Sat, Jan 2, 2016 at 3​:49 AM perl6 via RT <perl6-bugs-followup@​perl.org>
wrote​:

Greetings,

This message has been automatically generated in response to the
creation of a trouble ticket regarding​:
".wrap doesn't work for routines declared in roles",
a summary of which appears below.

There is no need to reply to this message right now. Your ticket has been
assigned an ID of [perl #​127112].

Please include the string​:

     \[perl #​127112\]

in the subject line of all future correspondence about this issue. To do
so,
you may reply to this message.

                    Thank you,
                    perl6\-bugs\-followup@​perl\.org

-------------------------------------------------------------------------
role Foo {
sub foo { };
BEGIN &foo.wrap(-> {});
}

From @LLFourn

I golfed this down to​:

p6 -e 'role {sub foo {}; BEGIN &foo.clone() }'

===SORRY!=== Error while compiling -e
An exception occurred while evaluating a BEGIN
at -e​:1
Exception details​:
  ===SORRY!=== Error while compiling
  Cannot invoke this object
  at :

For reasons I don't quite understand it's not using the right clone. If you
use Mu​::clone directly it works​:

p6 -e 'role {sub foo {}; BEGIN &foo.Mu​::clone() }'

On Sat, Jan 2, 2016 at 3​:58 AM Lloyd Fournier <lloyd.fourn@​gmail.com> wrote​:

should have mentioned, this is the error msg​:

===SORRY!=== Error while compiling
Cannot invoke this object

On Sat, Jan 2, 2016 at 3​:49 AM perl6 via RT <perl6-bugs-followup@​perl.org>
wrote​:

Greetings,

This message has been automatically generated in response to the
creation of a trouble ticket regarding​:
".wrap doesn't work for routines declared in roles",
a summary of which appears below.

There is no need to reply to this message right now. Your ticket has been
assigned an ID of [perl #​127112].

Please include the string​:

     \[perl #​127112\]

in the subject line of all future correspondence about this issue. To do
so,
you may reply to this message.

                    Thank you,
                    perl6\-bugs\-followup@​perl\.org

-------------------------------------------------------------------------
role Foo {
sub foo { };
BEGIN &foo.wrap(-> {});
}

From @lizmat

On 01 Jan 2016, at 17​:49, Lloyd Fournier (via RT) <perl6-bugs-followup@​perl.org> wrote​:

# New Ticket Created by Lloyd Fournier
# Please include the string​: [perl #​127112]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=127112 >

role Foo {
sub foo { };
BEGIN &foo.wrap(-> {});
}

One should realize that a role is nothing but a place-holder for code to be inserted when it is either does’d by a class, or punned into a class. It doesn't execute code in the mainline of the role after it has been parsed. Unless you use BEGIN of course.

If you remove the BEGIN from you example, I *think* it does what you expect it to​:

role Foo {
  sub foo { };
  &foo.wrap(-> { "foo" });

  say "mainline";

  method a { foo }
}

BEGIN say "role done";

say Foo.a

role done
mainline
foo

Note that the “mainline” is executed *after* the BEGIN block after the role.

Disallowing BEGIN blocks inside a role, might be an option. OTOH, there might be valid uses for that as well, doing MOPpy things.

So, all in all, I think this is a case of an LTA error. Is that what you intended to report?

Liz

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

From @LLFourn

Hey Liz,

Sorry this was a case of me golfing something down then not explaining the
.WHY of what I was originally doing. This is what I was trying to achieve.

multi trait_mod​:<is>(Routine​:D $meth,​:$baz!) {
  $meth.wrap( -> \SELF,$subj {});
};

role Foo {
  method foo is baz { };
}

Obviously traits are run at compile time. To me if you can't use a trait
that wraps a method in a role that's a very weird and annoying
inconsistency.

Also I don't think there is any architectural reason why methods in roles
can't be .wrap'd, I think it's just an edge case that hasn't been tested
for yet. As I showed above it's happening in .clone which for some reason
(which I would love to understand) is not Mu​::clone but some bootstrapping
clone​:

Lloyds-iMac​:~ llfourn$ perl6 -e 'sub foo { }; BEGIN
&foo.^find_method("clone").^name.say'
ForeignCode

On Sat, Jan 2, 2016 at 9​:14 PM Elizabeth Mattijsen via RT <
perl6-bugs-followup@​perl.org> wrote​:

On 01 Jan 2016, at 17​:49, Lloyd Fournier (via RT) <
perl6-bugs-followup@​perl.org> wrote​:

# New Ticket Created by Lloyd Fournier
# Please include the string​: [perl #​127112]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=127112 >

role Foo {
sub foo { };
BEGIN &foo.wrap(-> {});
}

One should realize that a role is nothing but a place-holder for code to
be inserted when it is either does’d by a class, or punned into a class.
It doesn't execute code in the mainline of the role after it has been
parsed. Unless you use BEGIN of course.

If you remove the BEGIN from you example, I *think* it does what you
expect it to​:

role Foo {
sub foo { };
&foo.wrap(-> { "foo" });

say "mainline";

method a \{ foo \}

}

BEGIN say "role done";

say Foo.a

role done
mainline
foo

Note that the “mainline” is executed *after* the BEGIN block after the
role.

Disallowing BEGIN blocks inside a role, might be an option. OTOH, there
might be valid uses for that as well, doing MOPpy things.

So, all in all, I think this is a case of an LTA error. Is that what you
intended to report?

Liz