No appropriate factory for type v

[mofeing]

I'm trying to use CxxWrap to wrap some C++ code from XLA, and i'm getting the following error:

C++ exception while wrapping module IFRT: No appropriate factory for type v
ERROR: LoadError: No appropriate factory for type v
Stacktrace:
  [1] register_julia_module
    @ ~/.julia/packages/CxxWrap/eWADG/src/CxxWrap.jl:424 [inlined]
  [2] readmodule(so_path_cb::Reactant.IFRT.var"#1#2", funcname::Symbol, m::Module, flags::Nothing)
    @ CxxWrap.CxxWrapCore ~/.julia/packages/CxxWrap/eWADG/src/CxxWrap.jl:815
  [3] wrapmodule(so_path_cb::Function, funcname::Symbol, m::Module, flags::Nothing)
    @ CxxWrap.CxxWrapCore ~/.julia/packages/CxxWrap/eWADG/src/CxxWrap.jl:825
  [4] top-level scope
    @ ~/Developer/Reactant.jl/src/IFRT.jl:6
  [5] include(mod::Module, _path::String)
    @ Base ./Base.jl:557
  [6] include(x::String)
    @ Reactant ~/Developer/Reactant.jl/src/Reactant.jl:1
  [7] top-level scope
    @ ~/Developer/Reactant.jl/src/Reactant.jl:149
  [8] include
    @ ./Base.jl:557 [inlined]
  [9] include_package_for_output(pkg::Base.PkgId, input::String, depot_path::Vector{String}, dl_load_path::Vector{String}, load_path::Vector{String}, concrete_deps::Vector{Pair{Base.PkgId, UInt128}}, source::Nothing)
    @ Base ./loading.jl:2881
 [10] top-level scope
    @ stdin:6
in expression starting at /Users/mofeing/Developer/Reactant.jl/src/IFRT.jl:1
in expression starting at /Users/mofeing/Developer/Reactant.jl/src/Reactant.jl:1

The code I'm trying to wrap is the class DType in here https://github.com/openxla/xla/blob/main/xla/python/ifrt/dtype.h
The class is actually quite simple. No parents, no virtual methods, ...

I have no problem wrapping the DType::Kind enum, but when I register DType like this

    mod.add_type<ifrt::DType>("DType");

I start getting the error.

I'm using CxxWrap v0.16.0 and libcxxwrap_julia v0.13.3

[mofeing]

I'm getting the same error with the example in README

struct World
{
  World(const std::string& message = "default hello") : msg(message){}
  World(jlcxx::cxxint_t) : msg("NumberedWorld") {}
  void set(const std::string& msg) { this->msg = msg; }
  const std::string& greet() const { return msg; }
  std::string msg;
  ~World() { std::cout << "Destroying World with message " << msg << std::endl; }
};

JLCXX_MODULE reactant_module_ifrt(jlcxx::Module& mod) {
  mod.add_type<World>("World");
}

some context: due to some symbol conflicts between XLA's LLVM and Julia's LLVM, we only export a list of symbols. i think that CxxWrap just needs access to the declared JLCXX_MODULE (i.e. reactant_module_ifrt) function, but in case there is sth more we need to export, i can add it to the greelist.

[mofeing]

So after a lot of tries, i can reproduce the error with only this line of code:

jlcxx::julia_return_type<void>();

jlcxx::create_if_not_exists<void>();