From @masak

<diakopter> r​: role popo { macro marco { $^a but popo }; marco popo; }
<camelia> rakudo 13f2f9​: OUTPUT«===SORRY!=== Error while compiling
/tmp/ix7YBbZNgR␤None of the parametric role variants for 'popo'
matched the arguments supplied.␤Null PMC access in get_pmc_keyed()␤at
/tmp/ix7YBbZNgR​:1␤------> ␤»
<diakopter> npmca. win.
* masak submits NPMCA rakudobug
<jnthn> Aaaaaad....it's called marco!
<masak> jnthn​: seems I can't prevent diakopter doing this.
* donaldh laughs his socks off

From @usev6

This no longer leads to a Null PMC access on Parrot (the output is identical on Moar and JVM)​:

$ perl6-p -e 'role popo { macro marco { $^a but popo }; marco popo; }'
===SORRY!=== Error while compiling -e
None of the parametric role variants for 'popo' matched the arguments supplied.
Cannot call ''; none of these signatures match​:
at -e​:1
------>

I added a test to S14-roles/mixin.t with commit Raku/roast@22a988135a.

I'm closing this ticket now. (In case the ticket was not only about the NPMCA and the command is meant to compile, please re-open the ticket.)

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