Compilation error due to a stubbed package that is never defined
class X::Package::Stubbed does X::Comp { }
Thrown at CHECK time when there are packages stubbed but not later defined.
For example
class A { ... } # literal ...
class B { ... } # literal ...
dies with
===SORRY!===
The following packages were stubbed but not defined:
A
B
method packages(--> Positional:D)
Returns a list of packages that were stubbed but not defined.