[ty] remove special handling for Any() in match class patterns#23011
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sharkdp merged 1 commit intoastral-sh:mainfrom Feb 2, 2026
Merged
[ty] remove special handling for Any() in match class patterns#23011sharkdp merged 1 commit intoastral-sh:mainfrom
Any() in match class patterns#23011sharkdp merged 1 commit intoastral-sh:mainfrom
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abhijeetbodas2001
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Any() in match class patterns
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| ## Class patterns where the class pattern does not resolve to a class | ||
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| In general this does not allow for narrowing, but we make an exception for `Any`. This is to support | ||
| [real ecosystem code](https://github.com/jax-ml/jax/blob/d2ce04b6c3d03ae18b145965b8b8b92e09e8009c/jax/_src/pallas/mosaic_gpu/lowering.py#L3372-L3387) | ||
| found in `jax`. | ||
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| ```py | ||
| from typing import Any | ||
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| X = Any | ||
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| def f(obj: object): | ||
| match obj: | ||
| case int(): | ||
| reveal_type(obj) # revealed: int | ||
| case X(): | ||
| reveal_type(obj) # revealed: Any & ~int | ||
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| def g(obj: object, Y: Any): | ||
| match obj: | ||
| case int(): | ||
| reveal_type(obj) # revealed: int | ||
| case Y(): | ||
| reveal_type(obj) # revealed: Any & ~int | ||
| ``` | ||
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Link to relevant discussion here: https://github.com/astral-sh/ruff/pull/21150/files#r2749631869
sharkdp
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This looks good to me, thank you!
I'll keep the referenced ticket open for now, because I think it makes sense to introduce a new diagnostic.
carljm
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Feb 2, 2026
* main: (48 commits) add info for non_octal permissions (#22972) Fix empty body rule rendering (#23039) [ty] Infer `ParamSpec` from class constructors for callable protocols (#22853) Update NPM Development dependencies (#23030) Update CodSpeedHQ/action action to v4.8.2 (#23029) [ty] remove special handling for `Any()` in match class patterns (#23011) Update Rust crate get-size2 to v0.7.4 (#23022) Update Rust crate insta to v1.46.1 (#23023) Update taiki-e/install-action action to v2.67.11 (#23033) Update Rust crate colored to v3.1.1 (#23031) Update cargo-bins/cargo-binstall action to v1.17.3 (#23028) Update Rust crate uuid to v1.20.0 (#23032) [ty] Avoid using `.node()` for detecting `Self` (#23000) Update Rust crate proc-macro2 to v1.0.106 (#23024) Update actions/setup-python action to v6.2.0 (#23027) [ty] fix query cycles in decorated function with parameter defaults (#23014) Update Rust crate quote to v1.0.44 (#23025) Update Rust crate thiserror to v2.0.18 (#23026) Update Rust crate filetime to v0.2.27 (#23021) Update Rust crate clearscreen to v4.0.3 (#23020) ...
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Summary
Anydoes not supportisinstancechecks and cannot be used in class patterns. If the arm withAny()is hit, it will raise an error at runtime:Because this fails at runtime, we should ideally raise a diagnostic on seeing
Any()in a match pattern. That could potentially be done as part of astral-sh/ty#2592. But for now, this PR only removes the special support that we have.The special-case handling does not reduce any diagnostics on
jaxas of today either.Test Plan
Removed tests :)