From @japhb

As seen at http://irclog.perlgeek.de/perl6/2011-09-24#i_4474816 :

23​:41 japhb nom​: 42 but role {}
23​:41 p6eval nom aed9fe​: ( no output )
23​:41 japhb nom​: 1/2 but role {}
23​:41 p6eval nom aed9fe​: OUTPUT«Not enough positional parameters passed;
got 1 but expected 3␤ in method BUILD at src/gen/CORE.setting​:5304␤ in
method BUILD_LEAST_DERIVED at src/gen/CORE.setting​:573␤ in sub
infix​:<but> at src/gen/CORE.setting​:7155␤ in <anon>
at /tmp/MBijIIXbzu​:1␤ in <anon> at /…
23​:41 japhb ^^ Wheee, another bug

Mixing a role into a Rat (either a literal one or as a variable) throws
the above weird error.

-'f

From @moritz

Now fixed in bfc3a42f5b3413479e11c9cfc9527dea6c52b85e, thanks to an
analysis by jnthn++. Needs tests.

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

From @moritz

now tested in S14-roles/mixin.t.

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