From @masak

In Rakudo b2e7ac, Parrot r36619​:

$ cat A.pm
use v6;
role A { method x(B $b) {} }
$ perl6 -e 'role B {}; use A; A.x(B)'
Null PMC access in isa()
[...]

Observations​:

* The role A must be imported for this to happen.
* The parameter in method x must refer to B.
* The argument to A.x doesn't actually have to be B, or of type B. The
error occurs anyway.

From @jnthn

On Thu Feb 12 01​:22​:34 2009, masak wrote​:

In Rakudo b2e7ac, Parrot r36619​:

$ cat A.pm
use v6;
role A { method x(B $b) {} }
$ perl6 -e 'role B {}; use A; A.x(B)'
Null PMC access in isa()
[...]

Observations​:

* The role A must be imported for this to happen.
* The parameter in method x must refer to B.
* The argument to A.x doesn't actually have to be B, or of type B. The
error occurs anyway.

Note that this should never "work" because of separate compilation. If
you pre-compiled A.pm it would fail telling you that you had a malformed
declaration (because type B did not exist). We just didn't give the
compiler a clean enough set of state so it thought B was acceptable, and
generated something that barfed at runtime instead.

Anyway, in git 703b36e I've now made sure we give a clean @​?BLOCK to the
recursive call into the compiler in a use, which means we fail at
compile time now, as we should.

Thanks,

Jonathan

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

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