sub wrapped with mod_trait:<is> when exported yield cryptic error message, works fine in same unit

[p6rt]

Migrated from rt.perl.org#129096 (status was 'open')

Searchable as RT129096$

[p6rt]

From ei@kefro.st

Tested on version 2016.07.1, 2016.08.1​:

When executing test2.pl, the error

Cannot invoke this object (REPR​: Null; VMNull)
  in block at (...)testimport.pm (testimport) line 7
  in any enter at gen/moar/m-Metamodel.nqp line 4012
  in block <unit> at test2.pl line 6

is displayed. When using the same code within the same file (i.e. without
an import of the wrapped sub), everything works as expected (i.e. output is

test, successfully wrapped
a

I asked about this in #perl6. It is not 100% clear that what I am trying to
do is supported​:

12​:25 < nine> ejf​: well you probably mean to export the wrapped sub but
that would mean that rakudo has to process the traits in the right way and
I'm not sure that's guaranteed. Could be that that's just a combination of
features
  that's not really feasible to support.
12​:26 < nine> ejf​: could also be just a plain straight forward bug in
rakudo :) I'm not familiar enough with that part to make a good guess and
am too tired to start debugging right now

(for reference, this also does not work if the trait_mod is part of an
exported class or is itself marked with "is export").

[p6rt]

From ei@kefro.st

test2.pl

[p6rt]

From ei@kefro.st

testimport.pm

[p6rt]

From @LLFourn

This is another outer context lost with compile time closure bug. It's one
of the most prolific bugs in rakudo :(.

I've added this ticket to the list​:

https://rt.perl.org/Public/Bug/Display.html?id=125634
https://rt.perl.org/Public/Bug/Display.html?id=126818
https://rt.perl.org/Public/Bug/Display.html?id=127034
https://rt.perl.org/Public/Bug/Display.html?id=127112
https://rt.perl.org/Public/Bug/Display.html?id=127858
https://rt.perl.org/Public/Bug/Display.html?id=127860
https://rt.perl.org/Public/Bug/Display.html?id=127959
https://rt.perl.org/Public/Bug/Display.html?id=107844
https://rt.perl.org/Public/Bug/Display.html?id=128636
https://rt.perl.org/Public/Bug/Display.html?id=129096

On Sat, 27 Aug 2016 at 10​:04 AM, Eike Frost <perl6-bugs-followup@​perl.org>
wrote​:

# New Ticket Created by Eike Frost
# Please include the string​: [perl #​129096]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl6/Ticket/Display.html?id=129096 >

Tested on version 2016.07.1, 2016.08.1​:

When executing test2.pl, the error

Cannot invoke this object (REPR​: Null; VMNull)
in block at (...)testimport.pm (testimport) line 7
in any enter at gen/moar/m-Metamodel.nqp line 4012
in block <unit> at test2.pl line 6

is displayed. When using the same code within the same file (i.e. without
an import of the wrapped sub), everything works as expected (i.e. output is

test, successfully wrapped
a

I asked about this in #perl6. It is not 100% clear that what I am trying to
do is supported​:

12​:25 < nine> ejf​: well you probably mean to export the wrapped sub but
that would mean that rakudo has to process the traits in the right way and
I'm not sure that's guaranteed. Could be that that's just a combination of
features
that's not really feasible to support.
12​:26 < nine> ejf​: could also be just a plain straight forward bug in
rakudo :) I'm not familiar enough with that part to make a good guess and
am too tired to start debugging right now

(for reference, this also does not work if the trait_mod is part of an
exported class or is itself marked with "is export").

[p6rt]

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