New semantic analyzer: plugin generated methods are confused with user defined ones

[ilevkivskyi]

This test case fails with new analyzer (note deferral):

[case testDataclassOrdering]
# flags: --python-version 3.6
from dataclasses import dataclass

defer: Yes

@dataclass(order=True)
class Application:
  name: str
  rating: int

class Yes: ...
[builtins fixtures/list.pyi]

with a bunch of errors

main:7: error: You may not have a custom __lt__ method when order=True
main:7: error: You may not have a custom __gt__ method when order=True
main:7: error: You may not have a custom __le__ method when order=True
main:7: error: You may not have a custom __ge__ method when order=True

Setting priority to high because it is a flaw in basic plugin functionality.

[christoph-blessing]

I think I am experiencing a related issue with mypy 0.910. Here is the offending code:

from collections.abc import Set
from dataclasses import dataclass

@dataclass(order=True)
class MySet(Set):
    pass

And here are the errors it produces:

test.py: error: You may not have a custom __lt__ method when order=True
test.py: error: You may not have a custom __gt__ method when order=True
test.py: error: You may not have a custom __le__ method when order=True
test.py: error: You may not have a custom __ge__ method when order=True
test.py:5: error: Only concrete class can be given where "Type[MySet]" is expected
test.py:6: error: Argument 1 of "__lt__" is incompatible with supertype "AbstractSet"; supertype defines the argument type as "AbstractSet[Any]"
test.py:6: note: This violates the Liskov substitution principle
test.py:6: note: See https://mypy.readthedocs.io/en/stable/common_issues.html#incompatible-overrides
test.py:6: error: Argument 1 of "__gt__" is incompatible with supertype "AbstractSet"; supertype defines the argument type as "AbstractSet[Any]"
test.py:6: error: Argument 1 of "__le__" is incompatible with supertype "AbstractSet"; supertype defines the argument type as "AbstractSet[Any]"
test.py:6: error: Argument 1 of "__ge__" is incompatible with supertype "AbstractSet"; supertype defines the argument type as "AbstractSet[Any]"
Found 9 errors in 1 file (checked 1 source file)

Setting order=False gets rid of all errors except this one:

test.py:5: error: Only concrete class can be given where "Type[MySet]" is expected

It also seems to be related to Set and MutableSet from collections.abc. I don't get this behavior with Mapping for example.

Any ideas what is happening here?

[JelleZijlstra]

Could you open a new issue? This is likely related to the typeshed definition for Set, so that's where I'd look.

[christoph-blessing]

Could you open a new issue? This is likely related to the typeshed definition for Set, so that's where I'd look.

Should I open the new issue in the mypy repo or in the typeshed repo?

[JelleZijlstra]

Let's start with mypy and transfer to typeshed if we find a concrete problem in the stubs.