From @masak

<Matt-W> rakudo​: module A​::B { role B { }; class D does A​::B​::B { } }
<p6eval> rakudo 41267f​: RESULT«{ ... }»
<Matt-W> see, no problem
<masak> no problem after putting the code in A/B.pm either, it seems.
<Matt-W> no
<Matt-W> but
<Matt-W> I made an A/A.pm which uses A​::B
<Matt-W> the test script uses A​::A
<Matt-W> and it says
<Matt-W> The type A​::B​::B does not exist. at line 6, near "{\n}\n\n\n"
<jnthn> Matt-W​: Does having the thingy you're using pre-compiled make
a difference?
<jnthn> Matt-W​: Also, do you do the "use" after a module A​::B; or
inside a module A​::B { }
<jnthn> If those two are true, I suspect I know what it is.
<Matt-W> don't know about precompilation, yes to the latter
<jnthn> Matt-W​: Bet it ain't getting a fresh @​?NS
<Matt-W> precompiling both modules makes it work
<Matt-W> in fact, precompiling just A/A.pm works
* masak submits rakudobug
<jnthn> Matt-W​: OK, I got a good idea then of what that is.
<Matt-W> jnthn++

From @jnthn

This ticket is a dupe of 63958, which has now been fixed; resolving.

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