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Enums: false-positive "No base classes allowed after ReprEnum" error #12787
Description
Bug Report
Minimal repro on 3.11 (playground link):
from enum import ReprEnum, Flag
class MyFlag(ReprEnum, Flag): ...Minimal repro on <=3.10 (playground link):
from enum import Enum, Flag
class ReprEnum(Enum): ...
class MyFlag(ReprEnum, Flag): ...mypy output for both (with small line-number differences):
main.py:4: error: No base classes are allowed after "__main__.ReprEnum" [misc]
Expected Behavior
No error should be reported. This use of multiple inheritance works fine at runtime on 3.10 and 3.11. In fact, in 3.11, the source code for the enum module in the stdlib uses exactly this inheritance structure:
class ReprEnum(Enum):
"""
Only changes the repr(), leaving str() and format() to the mixed-in type.
"""
# Much further down...
class IntFlag(int, ReprEnum, Flag, boundary=EJECT):
"""
Support for integer-based Flags
"""Your Environment
I can reproduce this bug on mypy 0.940+ (0.940 was the first released version with @sobolevn's #12026, which introduced this error message).
Activity
[-]Enums: false-positive "No base classes allowed" error[/-][+]Enums: false-positive "No base classes allowed after `Enum`" error[/+][-]Enums: false-positive "No base classes allowed after `Enum`" error[/-][+]Enums: false-positive "No base classes allowed after `ReprEnum`" error[/+]AlexWaygood commentedon May 14, 2022
An even simpler repro that doesn't involve
enum.Flag:This works fine at runtime, but mypy says:
Fix false-positive error on multiple enum base classes (#12963)
Fix false-positive error on multiple enum base classes (python#12963)