Hi all, now the following should work: .HLL "Foo", "Foo_group" .HLL_map .Sub, .FooSub .sub foo # typeof gives 'FooSub' ... (given that the HLL 'Foo' has defined a 'FooSub', which C<isa> Sub [1]) Closures and coroutines should be mappable too now. There is one test[2], which is showing that at least a subroutine of the correct type is created but not more. (Success) usage stories with existing HLLs welcome, leo [1] more precisely: it has to be a PMC, which extends Sub, overriding this type from PIR doesn't work due to different data layout) [2] t/dynpmc/sub.t