[ty] fix nested `NewType`s with add `Type::as_union_like` by oconnor663 · Pull Request #22997 · astral-sh/ruff

oconnor663 · 2026-01-31T04:13:49Z

This method was part of my implementation of astral-sh/ty#1656, but I found a bug in nested NewTypes of (surprise) float and complex that could be fixed by landing it separately, so I want to factor it out into its own PR.

This method was part of my implementation of astral-sh/ty#1656, but I found a bug in nested `NewType`s of (surprise) `float` and `complex` that could be fixed by landing it separately, so I want to factor it out into its own PR.

oconnor663 · 2026-01-31T04:14:40Z

crates/ty_python_semantic/src/types/newtype.rs

-            NewTypeBase::ClassType(_) | NewTypeBase::NewType(_) => false,
-            NewTypeBase::Float | NewTypeBase::Complex => true,
-        }
-    }


The issue with this helper is that it only inspected the immediate base type, as opposed to traversing all the way to the concrete (non-new-type) base. This is unlikely to be what any caller really wants.

astral-sh-bot · 2026-01-31T04:15:32Z

Typing conformance results

No changes detected ✅

oconnor663 · 2026-01-31T04:16:12Z

crates/ty_python_semantic/resources/mdtest/annotations/new_types.md

 ~Bar(1 + 2j)  # error: [unsupported-operator]
 reveal_type(not Bar(1 + 2j))  # revealed: bool
+reveal_type(-FooFoo(Foo(3.14)))  # revealed: int | float
+reveal_type(+FooFoo(Foo(3.14)))  # revealed: int | float


These two cases were failing before this PR. The others are added for good measure.

astral-sh-bot · 2026-01-31T04:16:48Z

`mypy_primer` results

Changes were detected when running on open source projects

prefect (https://github.com/PrefectHQ/prefect)
- src/integrations/prefect-dbt/prefect_dbt/core/settings.py:94:28: error[invalid-assignment] Object of type `dict[str, Any] | int | dict[Any, Any] | ... omitted 4 union elements` is not assignable to `dict[str, Any]`
- src/integrations/prefect-dbt/prefect_dbt/core/settings.py:99:28: error[invalid-assignment] Object of type `int | dict[Any, Any] | float | ... omitted 3 union elements` is not assignable to `dict[str, Any]`
- src/prefect/cli/deploy/_core.py:86:21: error[invalid-assignment] Object of type `dict[str, Any] | int | dict[Any, Any] | ... omitted 4 union elements` is not assignable to `dict[str, Any]`
- src/prefect/cli/deploy/_core.py:87:21: error[invalid-assignment] Object of type `int | dict[Any, Any] | float | ... omitted 3 union elements` is not assignable to `dict[str, Any]`
- src/prefect/deployments/runner.py:1017:70: warning[possibly-missing-attribute] Attribute `__name__` may be missing on object of type `Unknown | (((...) -> Any) & ((*args: object, **kwargs: object) -> object))`
+ src/prefect/deployments/runner.py:1017:70: warning[possibly-missing-attribute] Attribute `__name__` may be missing on object of type `Unknown | ((...) -> Any)`
- src/prefect/deployments/steps/core.py:137:38: error[invalid-argument-type] Argument is incorrect: Argument type `dict[str, Any] | int | dict[Any, Any] | ... omitted 4 union elements` does not satisfy constraints (`str`, `int`, `int | float`, `bool`, `dict[Any, Any]`, `list[Any]`, `None`) of type variable `T`
+ src/prefect/flow_engine.py:997:32: error[invalid-await] `Unknown | R@FlowRunEngine | Coroutine[Any, Any, R@FlowRunEngine]` is not awaitable
+ src/prefect/flow_engine.py:1596:24: error[invalid-await] `Unknown | R@AsyncFlowRunEngine | Coroutine[Any, Any, R@AsyncFlowRunEngine]` is not awaitable
+ src/prefect/flow_engine.py:1677:43: error[invalid-argument-type] Argument to function `next` is incorrect: Expected `SupportsNext[Unknown]`, found `Unknown | R@run_generator_flow_sync`
+ src/prefect/flow_engine.py:1685:21: warning[possibly-missing-attribute] Attribute `throw` may be missing on object of type `Unknown | R@run_generator_flow_sync`
+ src/prefect/flow_engine.py:1719:44: warning[possibly-missing-attribute] Attribute `__anext__` may be missing on object of type `Unknown | R@run_generator_flow_async`
+ src/prefect/flow_engine.py:1726:25: warning[possibly-missing-attribute] Attribute `throw` may be missing on object of type `Unknown | R@run_generator_flow_async`
- src/prefect/flows.py:285:34: error[unresolved-attribute] Object of type `((**P@Flow) -> R@Flow) & ((*args: object, **kwargs: object) -> object)` has no attribute `__name__`
+ src/prefect/flows.py:285:34: error[unresolved-attribute] Object of type `(**P@Flow) -> R@Flow` has no attribute `__name__`
- src/prefect/flows.py:403:68: error[unresolved-attribute] Object of type `((**P@Flow) -> R@Flow) & ((*args: object, **kwargs: object) -> object)` has no attribute `__name__`
+ src/prefect/flows.py:403:68: error[unresolved-attribute] Object of type `(**P@Flow) -> R@Flow` has no attribute `__name__`
- src/prefect/flows.py:1885:53: warning[unused-type-ignore-comment] Unused blanket `type: ignore` directive
+ src/prefect/flows.py:1945:21: error[no-matching-overload] No overload of function `run_coro_as_sync` matches arguments
- src/prefect/utilities/templating.py:320:13: error[invalid-assignment] Invalid subscript assignment with key of type `object` and value of type `dict[str, Any] | int | Unknown | ... omitted 4 union elements` on object of type `dict[str, Any]`
+ src/prefect/utilities/templating.py:320:13: error[invalid-assignment] Invalid subscript assignment with key of type `object` and value of type `Unknown | dict[str, Any]` on object of type `dict[str, Any]`
- src/prefect/utilities/templating.py:323:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_block_document_references | dict[str, Any]`, found `list[Unknown | dict[str, Any] | int | ... omitted 4 union elements]`
+ src/prefect/utilities/templating.py:323:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_block_document_references | dict[str, Any]`, found `list[Unknown | dict[str, Any]]`
- src/prefect/utilities/templating.py:437:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_variables`, found `dict[object, Unknown | int | float | ... omitted 4 union elements]`
+ src/prefect/utilities/templating.py:437:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_variables`, found `dict[object, Unknown]`
- src/prefect/utilities/templating.py:442:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_variables`, found `list[Unknown | int | float | ... omitted 4 union elements]`
+ src/prefect/utilities/templating.py:442:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_variables`, found `list[Unknown]`
+ src/prefect/workers/base.py:232:13: error[invalid-argument-type] Argument is incorrect: Argument type `str | dict[str, Any]` does not satisfy constraints (`str`, `int`, `int | float`, `bool`, `dict[Any, Any]`, `list[Any]`, `None`) of type variable `T`
- src/prefect/workers/base.py:232:13: error[invalid-argument-type] Argument is incorrect: Argument type `dict[str, Any] | int | str | ... omitted 3 union elements` does not satisfy constraints (`str`, `int`, `int | float`, `bool`, `dict[Any, Any]`, `list[Any]`, `None`) of type variable `T`
- src/prefect/workers/base.py:234:22: error[invalid-argument-type] Argument expression after ** must be a mapping type: Found `int | Unknown | float | ... omitted 4 union elements`

No memory usage changes detected ✅

carljm

Nice!

[ty] fix nested NewTypes with add Type::as_union_like

51e0132

This method was part of my implementation of astral-sh/ty#1656, but I found a bug in nested `NewType`s of (surprise) `float` and `complex` that could be fixed by landing it separately, so I want to factor it out into its own PR.

oconnor663 requested review from AlexWaygood, carljm, dcreager and sharkdp as code owners January 31, 2026 04:13

oconnor663 commented Jan 31, 2026

View reviewed changes

AlexWaygood added the ty Multi-file analysis & type inference label Jan 31, 2026

carljm approved these changes Feb 2, 2026

View reviewed changes

oconnor663 merged commit 4a32a96 into main Feb 2, 2026
50 checks passed

oconnor663 deleted the jack/as_union_like branch February 2, 2026 20:16

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[ty] fix nested `NewType`s with add `Type::as_union_like`#22997

[ty] fix nested `NewType`s with add `Type::as_union_like`#22997
oconnor663 merged 1 commit intomainfrom
jack/as_union_like

oconnor663 commented Jan 31, 2026

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oconnor663 commented Jan 31, 2026

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`mypy_primer` results