I think I have an idea why this may be missing, but anyway this is probably not important since you don't need this anyway, everywhere where you use base.defn.info you can use just base, this is the same object.

understood!

You don't need this to be a cycle, just use method_symbol_node = base.names.get('__init_subclass__').

Or even simpler (if you are not going to use method_symbol_node):

if '__init_subclass__' not in base.names:
    continue

you are right, I have modified accordingly

Using accept() may actually be dangerous. For example if the base class is not in scope (defined in another module and not imported in the current one), this may trigger Name not defined or maybe even a crash. There are two possible solutions here:

• Point name_expr.node to the base class TypeInfo before calling accept()
• Use check_call() or similar methods

Please add a test for this.

Hm sorry, I don't understand. I tried to produce a mypy runtime exception with 2 modules, one of which defines a Base, and the other one doesn't import that Base, and it only gave me a nice error Name 'Base' is not defined. Which os OK I guess? this is what would happen at runtime anyway (NameError: name 'Base' is not defined)

I added a test for that

Which os OK I guess?

It is not what I wanted. I wanted something like this:

# file bases.py
class Base:
    def __init_subclass__(cls, **kwargs) -> None: ...
class MidBase(Base):
    ...
# file main.py
from bases import MidBase
class Main(MidBase, test=False):
    ...