Tracking: Enabling more `pyright` rules

[dangotbanned]

Description

We have most of the rules disabled, but there are some interesting ones hidden away.

I'm mainly interested in things that mypy currently catches, but pyright could've warned earlier.
Things unique to pyright could be nice, but a lot of them seem to be covered by ruff

Not in any rush to do this btw

Specific Rules

• reportOverlappingOverload

PRs

• chore(typing): enable reportIncompatibleMethodOverride in pyright #3096
• chore: enable pyright reportPossiblyUnboundVariable #2584

Misc

#3096 (comment)

Oooh also it reminded me of trying out typeCheckingMode = "strict" a couple months back

reportUnusedExpression = "none"    # handled by (https://docs.astral.sh/ruff/rules/unused-variable/)
+ # strict
+ reportUnusedVariable = "none"      # handled by (https://docs.astral.sh/ruff/rules/unused-variable/)
+ reportUnusedClass = "none"
+ reportUnusedFunction = "none"
+ reportPrivateUsage = "none"
+ reportUnknownVariableType = "none"
+ reportUnknownArgumentType = "none"
+ reportUnknownMemberType = "none"
+ reportUnknownLambdaType = "none"
+ reportMissingTypeStubs = "none"
+ typeCheckingMode = "strict" # strict = 3545 errors

I'd gotten the branch down to 81 errors (June 26, 2025), and reportIncompatibleMethodOverride I thought we should keep as well 🙂

[dangotbanned]

Back in (#2972 (comment)), I mentioned overlapping overloads

Ah right so both this one and (#2972 (comment)) are to do with overlapping overloads

I might be able to do a repro later, but the general idea is:

• in python's typing float means int | float (because reasons 😭)
• in python's runtime, bool subclasses int (because PEP 285)

So I was trying to make use of Literal to avoid overlaps

Well, it turns out that was an issue - we just didn't have the rule enabled 🤦‍♂️

By adding it here (as I just did for double-checking #3125):

# pyproject.toml

[tool.pyright]
reportOverlappingOverload = "error"

pyright will then start reporting the issue

narwhals/_ibis/utils.py:33:5 
error: Overload 1 for "lit" overlaps overload 2 and returns an incompatible type (reportOverlappingOverload)
error: Overload 1 for "lit" overlaps overload 3 and returns an incompatible type (reportOverlappingOverload)

narwhals/narwhals/_ibis/utils.py

Lines 32 to 37 in 556c6a6

	@overload
	def lit(value: bool, dtype: None = ...) -> ir.BooleanScalar: ... # noqa: FBT001
	@overload
	def lit(value: int, dtype: None = ...) -> ir.IntegerScalar: ...
	@overload
	def lit(value: float, dtype: None = ...) -> ir.FloatingScalar: ...