Unexpected incompatible types in assignment (Failed in recursive type checking, nested protocol with generic type)
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Description
Bug Report
Here I write some nested protocol with generic type.
The basic protocol classes with generic type succeed to match the classes written in the pyi file, like this:
t: Tempo[int] = core.TempoTick(0, 0) # pass
t: Temop = core.TemoTick(0,0) # pass
However, for upper layer class, list List[Tempo], it just started to fail (with generic), like this:
Note that List is a self defined protocol here for classes generated by pybind11 bind_vector
tempos2: List[Tempo] = core.TempoTickList() # not pass
tempos3: List = core.TempoTickList() # pass
The full errors are listed here:
Incompatible types in assignment (expression has type "TempoTickList", variable has type "symusic.types.List[Tempo[Any]]")Mypy[assignment](https://mypy.readthedocs.io/en/latest/_refs.html#code-assignment)
Following member(s) of "TempoTickList" have conflicts:
Expected:
@overload
def __setitem__(self, int, Tempo[Any], /) -> None
@overload
def __setitem__(self, slice, TempoTickList, /) -> None
Got:
@overload
def __setitem__(self, int, TempoTick, /) -> None
@overload
def __setitem__(self, slice, TempoTickList, /) -> None
Expected:
def append(self, x: Tempo[Any]) -> None
Got:
def append(self, x: TempoTick) -> None
<1 more conflict(s) not shown>Mypy
Although Tempo and Tempo[int] have matched TempoTick, they are said failed to match in the errors.
Even if I remove some of the nested generic type like below, it still failed:
class Score(Protocol[TimeDtype]):
ticks_per_quarter: int
tracks: List
key_signatures: List
time_signatures: List
tempos: List
lyrics: List
markers: List
By the way, in pycharm, it says, all of these classes fail to match, quite different from mypy. And different from mypy, pycharm don't offer me any useful debug information. (But pycharm works as expected in my following test while mypy failed. So I guess there are at least 2 problems in total.)
To Reproduce
I put my codes here (just a few files):
symusic.zip
And the code in picture is at the bottom of the types.py. I just use the vscode MyPy Type Checker plugin.
Expected Behavior
Well, I just expect it to match.
Actual Behavior
They don't match when the protocol with generic type is nested
Your Environment
- Mypy version used: mypy 1.7.1 (compiled: yes)
- Mypy command-line flags: default in vscode
- Mypy configuration options from
mypy.ini(and other config files): default - Python version used: 3.11.6
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the attached symusic.zip reproduction, especially the code at the bottom of types.py, and run it with mypy 1.7.1 using the default configuration. Compare the nested generic protocol assignments with the reported errors; done means the TempoTickList and related protocol assignments are accepted consistently with the simpler cases.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100