Errors when calling jlcxx::make_function_pointer

[benjaminfaber]

Hi, I am attempting to use CxxWrap to expose a C++ library to Julia, and I would like to pass a Julia function as a callback to the library. However, when I attempt to use jlcxx::make_function_pointer, I receive an error that some of the arguments of the signature for the function pointer I'm attempting to convert have no Julia wrapper. A MWE is below:

#include "jlcxx/jlcxx.hpp"
#include "jlcxx/functions.hpp"

class test_class {
};

JLCXX_MODULE define_julia_module(jlcxx::Module& mod) {
  mod.method("pass_func",[](jlcxx::SafeCFunction f_data) {
    auto f = jlcxx::make_function_pointer<void(int*,test_class*)>(f_data);
    });
}

julia> module wrapped
            using CxxWrap
            @wrapmodule(joinpath("lib/path","lib"))
            function __init__()
              @initcxx
            end
          end

julia> function testfunc(i::Int,c::wrapped.test_class)
          end

julia> cxxtestfunc = @safe_cfunction(testfunc, Cvoid, (CxxPtr{Cint},CxxPtr{wrapped.test_class}));

julia> wrapped.pass_func(cxxtestfunc)
ERROR: Type Pi has no Julia wrapper

This error does not arise if a double* is specified in the function pointer signature, which makes me think this is a bug, or am I just using libcxxwrap incorrectly?