pdb (and other Python debuggers) are built on top of bdb.py module.

The module has a support for stepping to next line in function (next command).

The command checks frame flags and do extra steps if the flags contains CO_GENERATOR.

But CO_COROUTINE is not supported, it leads to stepping into a native coroutine instead of expecting stepping over.

The patch should be relative simple: just add a check for CO_COROUTINE along with CO_GENERATOR everywhere.