Repository navigation
[1.16 regression] assigning a lambda to subclass w/ generics #19165
Description
Bug Report
Consider the following:
https://mypy-play.net/?mypy=latest&python=3.12&gist=29ddead67873ff6c1f1bf36de8726bd7
This works without error in 1.15 mypy. But in the new 1.16 version, one would see Incompatible return value type (got "int", expected "T") on converter2
Your Environment
- Mypy version used: 1.16
- Mypy command-line flags: (defaults)
- Mypy configuration options from
mypy.ini(and other config files): n/a - Python version used: 3.11 & 3.12
Activity
[-]'Incompatible return value type (... expected "T")' when assigning a lambda to a class w/ generics[/-][+][1.16 regression] assigning a lambda to subclass w/ generics[/+]hauntsaninja commentedon May 29, 2025
This will be #18847
ilevkivskyi commentedon May 30, 2025
I will take a look at this (hopefully during weekend). Most likely I just missed some edge case (since it works for non-lambda overrides).
ilevkivskyi commentedon May 31, 2025
Oh well, this is fixed on master now by #18943. I am not sure however if it is worth including in a point release, as this is a big PR and regression doesn't seem urgent. Anyway, I will leave this decision up to @JukkaL
Redoubts commentedon May 31, 2025
Since there’s an obvious workaround, I’m not too pressed about letting this float to the next real release