[JVM] Module shadowed after importing another module (precompilation involved)

[usev6]

The Problem

I tried to get Zef to work on the JVM backend (with the changes from Raku/nqp#643 applied), but ran into the following error:

$ rakudo-j -I. -Ilib bin/zef install .
Could not find symbol '&Client' in 'Zef'

I tried to golf the problem down and arrived at this:

$ cat lib/Foo.pm6 
class Foo { }
$ cat lib/Foo/A.pm6 
use Foo::B;
use Foo::C;
class Foo::A { my $b = Foo::B.new }
$ cat lib/Foo/B.pm6 
use Foo;
class Foo::B { }
$ cat lib/Foo/C.pm6 
#no precompilation;
use Foo;
class Foo::C { }
$ rakudo-j -Ilib -e 'use Foo::A; my $a = Foo::A.new'
===SORRY!=== Error while compiling -e
Could not find symbol '&B' in 'Foo'
at -e:1

If I uncomment no precompilation for Foo::C the error goes away:

$ sed -i -e '/^#no precompilation;/ s/^#//' lib/Foo/C.pm6
$ rakudo-j -Ilib -e 'use Foo::A; my $a = Foo::A.new'
$

Environment

• Operating system: FreeBSD 11.3-RELEASE-p6
• Compiler version (perl6 -v or raku -v): This is Rakudo version 2020.06-60-g07009cc0d built on JVM