The beta works great this far, just sharing some few initial surprises. 1) The lookup rules for namespaces seem overly permissive: extern (C++, A.B.C): void cpp() { } All these work: A.cpp B.cpp C.cpp A.B.cpp B.C.cpp A.B.C.cpp 2) We have std.traits.functionLinkage, but no corresponding trait to get the namespace?