From @moritz

<moritz> r​: my $a = []; my $role = role { has $.cool = "yeah" }; $a does
  $role; say $a.cool
<camelia> rakudo-parrot 9ff0bc​: OUTPUT«yeah␤»
<camelia> ..rakudo-jvm 9ff0bc​: OUTPUT«Nominal type check failed for
  parameter 'null'␤ in method at /tmp/tmpfile​:1␤ in block at
  gen/jvm/CORE.setting​:993␤ in method BUILD_LEAST_DERIVED at
  gen/jvm/CORE.setting​:951␤ in sub infix​:<does> at
  gen/jvm/CORE.setting​:16514␤ in sub infix​:<d…»
<camelia> ..rakudo-moar 9ff0bc​: OUTPUT«Type check failed in binding
  <anon>; expected '<anon>' but got 'Array+{<anon>}'␤ in method
  at /tmp/tmpfile​:1␤ in block at src/gen/m-CORE.setting​:993␤
  in method BUILD_LEAST_DERIVED at src/gen/m-CORE.setting​:951␤
  in sub infix​:<does> at src/gen/…»

But this one works​:

<moritz> r​: my $a = []; $a does role { has $.cool = "yeah" }; say $a.cool
<camelia> rakudo-parrot 9ff0bc, rakudo-jvm 9ff0bc, rakudo-moar 9ff0bc​:
OUTPUT«yeah␤»

This cases test failures in t/spec/S14-roles/anonymous.t

From @moritz

Tests pass again => resolving.

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