Huh, interesting - I'd missed that the only part of the "from a.b import c" that IMPORT_FROM implements is the LOAD_ATTR variant that falls back to sys.modules. The prior adjustment to get IMPORT_NAME to return "a.b" instead of "a" happens inside that opcode based on the fact that a non-empty from_list was passed in.

So indeed, there's no new opcode needed - as Serhiy points out, the compiler just needs to emit IMPORT_FROM instead of LOAD_ATTR for this case.