> Yes, of course.:) BTW this behaviour was introduced long before my pull.

Yes, I know how the c++ mangler works...

> Anyway, hard mangling (like C++) should be constructed in front-end, because front-end should define D types mapping to other language. We was have any troubles when C++ mangling was constructed in backend (or glue). And if mangle is builded in front-end, we can return it from .mangleof. And I think, we should do it.

The problem never was to do with mangling symbols declarated with extern(C++) in the frontend.

> For simple mangling "like C, Pascal, Stdcall", we can build it in front-end without any efforts.

C, Pascal, and stdcall do not have any mangling scheme that's required to be defined by the front end.  If you wish to define a mangling convention for C, Pascal and stdcall to be included in D, this raise a DIP and request a new feature.