[ty] Add diagnostics to validate TypeIs and TypeGuard definitions#22300
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charliermarsh merged 1 commit intomainfrom Jan 14, 2026
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[ty] Add diagnostics to validate TypeIs and TypeGuard definitions#22300charliermarsh merged 1 commit intomainfrom
TypeIs and TypeGuard definitions#22300charliermarsh merged 1 commit intomainfrom
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Diagnostic diff on typing conformance testsChanges were detected when running ty on typing conformance tests--- old-output.txt 2026-01-13 23:29:49.973606373 +0000
+++ new-output.txt 2026-01-13 23:29:50.352609209 +0000
@@ -762,16 +762,22 @@
namedtuples_usage.py:43:5: error[not-subscriptable] Cannot delete subscript on object of type `Point` with no `__delitem__` method
namedtuples_usage.py:52:1: error[invalid-assignment] Too many values to unpack: Expected 2
namedtuples_usage.py:53:1: error[invalid-assignment] Not enough values to unpack: Expected 4
+narrowing_typeguard.py:102:23: error[invalid-type-guard-definition] `TypeGuard` function must have a parameter to narrow
+narrowing_typeguard.py:107:22: error[invalid-type-guard-definition] `TypeGuard` function must have a parameter to narrow
narrowing_typeguard.py:128:20: error[invalid-argument-type] Argument to function `takes_callable_str` is incorrect: Expected `(object, /) -> str`, found `def simple_typeguard(val: object) -> TypeGuard[int]`
narrowing_typeguard.py:148:26: error[invalid-argument-type] Argument to function `takes_callable_str_proto` is incorrect: Expected `CallableStrProto`, found `def simple_typeguard(val: object) -> TypeGuard[int]`
narrowing_typeis.py:21:9: error[type-assertion-failure] Type `tuple[str, ...]` does not match asserted type `tuple[str, ...] & ~tuple[str, str]`
narrowing_typeis.py:35:18: error[invalid-assignment] Object of type `object` is not assignable to `int`
narrowing_typeis.py:38:9: error[type-assertion-failure] Type `int` does not match asserted type `int & ~Awaitable[object]`
+narrowing_typeis.py:105:23: error[invalid-type-guard-definition] `TypeIs` function must have a parameter to narrow
+narrowing_typeis.py:110:22: error[invalid-type-guard-definition] `TypeIs` function must have a parameter to narrow
narrowing_typeis.py:132:20: error[invalid-argument-type] Argument to function `takes_callable_str` is incorrect: Expected `(object, /) -> str`, found `def simple_typeguard(val: object) -> TypeIs[int]`
narrowing_typeis.py:152:26: error[invalid-argument-type] Argument to function `takes_callable_str_proto` is incorrect: Expected `CallableStrProto`, found `def simple_typeguard(val: object) -> TypeIs[int]`
narrowing_typeis.py:169:17: error[invalid-argument-type] Argument to function `takes_typeguard` is incorrect: Expected `(object, /) -> TypeGuard[int]`, found `def is_int_typeis(val: object) -> TypeIs[int]`
narrowing_typeis.py:170:14: error[invalid-argument-type] Argument to function `takes_typeis` is incorrect: Expected `(object, /) -> TypeIs[int]`, found `def is_int_typeguard(val: object) -> TypeGuard[int]`
narrowing_typeis.py:191:18: error[invalid-argument-type] Argument to function `takes_int_typeis` is incorrect: Expected `(object, /) -> TypeIs[int]`, found `def bool_typeis(val: object) -> TypeIs[bool]`
+narrowing_typeis.py:195:27: error[invalid-type-guard-definition] Narrowed type `str` is not assignable to the declared parameter type `int`
+narrowing_typeis.py:199:45: error[invalid-type-guard-definition] Narrowed type `list[int]` is not assignable to the declared parameter type `list[object]`
overloads_basic.py:39:1: error[invalid-argument-type] Method `__getitem__` of type `Overload[(__i: int, /) -> int, (__s: slice[Any, Any, Any], /) -> bytes]` cannot be called with key of type `Literal[""]` on object of type `Bytes`
overloads_definitions.py:20:5: error[invalid-overload] Overloaded function `func1` requires at least two overloads
overloads_definitions.py:33:5: error[invalid-overload] Overloads for function `func2` must be followed by a non-`@overload`-decorated implementation function
@@ -1029,4 +1035,4 @@
typeddicts_usage.py:28:17: error[missing-typed-dict-key] Missing required key 'name' in TypedDict `Movie` constructor
typeddicts_usage.py:28:18: error[invalid-key] Unknown key "title" for TypedDict `Movie`: Unknown key "title"
typeddicts_usage.py:40:24: error[invalid-type-form] The special form `typing.TypedDict` is not allowed in type expressions
-Found 1031 diagnostics
+Found 1037 diagnostics
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hmm, can we either add some snapshots here or assert the error message in some of these # error: comments? Currently it's a bit hard to see why we're complaining about each line, and what the message presented to the user would be
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The ecosystem diagnostics on mypy are weird, but I'm guessing it's the usual confusion of us not understanding the |
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Jan 14, 2026
…#22300) ## Summary Closes astral-sh/ty#2267.
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Summary
Closes astral-sh/ty#2267.