Allow partial overlap when checking overload alternatives

[dlax]

Description

Fixes #11004

The following case defines a function with both an explicit keyword argument and **kwargs but with types incompatible (int for the explicit one, str for **kwargs):

from typing import Optional, overload

@overload
def f(x: int = 0, **kwargs: str) -> None:
    ...
@overload
def f(x: int = 0, *, y: int, **kwargs: str) -> str:
    ...
def f(x: int = 0, *, y: Optional[int] = None, **kwargs: str) -> Optional[str]:
# E: Overloaded function implementation does not accept all possible arguments of signature 1
    ...

reveal_type(f(0))
# N: Revealed type is "None"
reveal_type(f(1, foo='bar'))
# N: Revealed type is "None"
reveal_type(f(1, y=2, foo='bar'))
# N: Revealed type is "builtins.str"

Mypy raises an error "Overloaded function implementation does not accept all possible arguments of signature 1" but types are correctly inferred, so the error seems to be a false-positive.

Allowing partial overlap when checking compatibility between one overload alternative and the implementation fixes the issue (the error is no longer raised). Calling is_callable_compatible(..., allow_partial_overlap=True) is documented to "return True if there exists at least one call to left that's also a call to right"; which seems valid for overloads.

(This appears so simple that it's quite possible that I missed something...)

Test Plan

Example above is included as a test case. No apparent breakage in the test suite.

[adam-grant-hendry]

@dlax Is this planned to be merged soon?

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

steam.py (https://github.com/Gobot1234/steam.py)
- steam/utils.py:539: error: Overloaded function implementation does not accept all possible arguments of signature 2  [misc]
+ steam/ext/commands/commands.py:802: error: Unused "type: ignore" comment  [unused-ignore]
- steam/ext/commands/commands.py:851: error: Overloaded function implementation does not accept all possible arguments of signature 3  [misc]
- steam/ext/commands/cog.py:53: error: Overloaded function implementation does not accept all possible arguments of signature 1  [misc]

jinja (https://github.com/pallets/jinja)
+ src/jinja2/filters.py:1368: error: Overloaded function implementation does not accept all possible arguments of signature 2  [misc]

tornado (https://github.com/tornadoweb/tornado)
+ tornado/gen.py:177: error: Overloaded function implementation does not accept all possible arguments of signature 2  [misc]

spark (https://github.com/apache/spark)
+ python/pyspark/rdd.py:4304: error: Unused "type: ignore" comment  [unused-ignore]
+ python/pyspark/sql/dataframe.py:1908: error: Unused "type: ignore" comment  [unused-ignore]
+ python/pyspark/sql/dataframe.py:2041: error: Unused "type: ignore" comment  [unused-ignore]
+ python/pyspark/sql/dataframe.py:6414: error: Unused "type: ignore" comment  [unused-ignore]
+ python/pyspark/sql/connect/dataframe.py:298: error: Unused "type: ignore" comment  [unused-ignore]
+ python/pyspark/sql/connect/dataframe.py:345: error: Unused "type: ignore" comment  [unused-ignore]

hydra-zen (https://github.com/mit-ll-responsible-ai/hydra-zen)
- src/hydra_zen/typing/_builds_overloads.py:238: error: Overloaded function implementation does not accept all possible arguments of signature 3  [misc]
+ src/hydra_zen/typing/_builds_overloads.py:238: error: Overloaded function implementation does not accept all possible arguments of signature 2  [misc]
- src/hydra_zen/typing/_builds_overloads.py:238: error: Overloaded function implementation does not accept all possible arguments of signature 5  [misc]
- src/hydra_zen/typing/_builds_overloads.py:238: error: Overloaded function implementation does not accept all possible arguments of signature 7  [misc]
- src/hydra_zen/typing/_builds_overloads.py:472: error: Overloaded function implementation does not accept all possible arguments of signature 2  [misc]
+ src/hydra_zen/typing/_builds_overloads.py:472: error: Overloaded function implementation does not accept all possible arguments of signature 3  [misc]
- src/hydra_zen/typing/_builds_overloads.py:472: error: Overloaded function implementation does not accept all possible arguments of signature 4  [misc]
- src/hydra_zen/typing/_builds_overloads.py:472: error: Overloaded function implementation does not accept all possible arguments of signature 6  [misc]
- src/hydra_zen/typing/_builds_overloads.py:472: error: Overloaded function implementation does not accept all possible arguments of signature 8  [misc]
- src/hydra_zen/typing/_builds_overloads.py:657: error: Overloaded function implementation does not accept all possible arguments of signature 1  [misc]
- src/hydra_zen/typing/_builds_overloads.py:657: error: Overloaded function implementation does not accept all possible arguments of signature 5  [misc]
+ src/hydra_zen/typing/_builds_overloads.py:657: error: Overloaded function implementation does not accept all possible arguments of signature 4  [misc]
+ src/hydra_zen/typing/_builds_overloads.py:657: error: Overloaded function implementation does not accept all possible arguments of signature 7  [misc]

[dlax]

Rebased and resolved conflicts.