[ty] Type narrowing in comprehensions

[sharkdp]

Summary

Add type narrowing inside comprehensions:

def _(xs: list[int | None]):
    [reveal_type(x) for x in xs if x is not None]  # revealed: int

closes astral-sh/ty#680

Test Plan

• New Markdown tests
• Made sure the example from list comprehension with None (falsy) values filtered by condition ty#680 now checks without errors
• Made sure that all removed ecosystem diagnostics were actually false positives

[github-actions]

mypy_primer results

Changes were detected when running on open source projects

kornia (https://github.com/kornia/kornia)
- warning[possibly-unbound-attribute] kornia/geometry/transform/affwarp.py:816:24: Attribute `size` on type `Unknown | None` is possibly unbound
- Found 805 diagnostics
+ Found 804 diagnostics

kopf (https://github.com/nolar/kopf)
- warning[possibly-unbound-attribute] kopf/_core/engines/admission.py:429:20: Attribute `check` on type `Selector | None` is possibly unbound
- Found 131 diagnostics
+ Found 130 diagnostics

graphql-core (https://github.com/graphql-python/graphql-core)
- error[unresolved-attribute] src/graphql/validation/rules/possible_type_extensions.py:35:13: Type `DefinitionNode` has no attribute `name`
- Found 382 diagnostics
+ Found 381 diagnostics

flake8-pyi (https://github.com/PyCQA/flake8-pyi)
- error[unresolved-attribute] flake8_pyi/visitor.py:2090:17: Type `expr` has no attribute `id`
- Found 10 diagnostics
+ Found 9 diagnostics

ppb-vector (https://github.com/ppb/ppb-vector)
- error[invalid-argument-type] tests/utils.py:62:15: Argument to function `abs` is incorrect: Expected `SupportsAbs[Unknown]`, found `int | float | Vector`
- warning[possibly-unbound-attribute] tests/utils.py:63:11: Attribute `length` on type `int | float | Vector` is possibly unbound
- Found 21 diagnostics
+ Found 19 diagnostics

schemathesis (https://github.com/schemathesis/schemathesis)
- warning[possibly-unbound-attribute] src/schemathesis/cli/commands/run/handlers/output.py:1051:27: Attribute `id` on type `Transition | None` is possibly unbound
- Found 311 diagnostics
+ Found 310 diagnostics

pytest (https://github.com/pytest-dev/pytest)
- error[unresolved-attribute] src/_pytest/assertion/rewrite.py:1032:25: Type `expr` has no attribute `id`
- Found 641 diagnostics
+ Found 640 diagnostics

pywin32 (https://github.com/mhammond/pywin32)
- error[non-subscriptable] win32/Demos/win32wnet/testwnet.py:61:21: Cannot subscript object of type `None` with no `__getitem__` method
- error[non-subscriptable] win32/test/test_win32wnet.py:148:25: Cannot subscript object of type `None` with no `__getitem__` method
- Found 2115 diagnostics
+ Found 2113 diagnostics

psycopg (https://github.com/psycopg/psycopg)
- warning[possibly-unbound-attribute] psycopg/psycopg/conninfo.py:84:31: Attribute `decode` on type `bytes | None` is possibly unbound
- warning[possibly-unbound-attribute] tests/pq/test_pgconn.py:136:33: Attribute `decode` on type `bytes | None` is possibly unbound
- warning[possibly-unbound-attribute] tests/pq/test_pgconn.py:141:33: Attribute `decode` on type `bytes | None` is possibly unbound
- Found 906 diagnostics
+ Found 903 diagnostics

scrapy (https://github.com/scrapy/scrapy)
- error[unresolved-attribute] scrapy/item.py:38:27: Type `type` has no attribute `_class`
- Found 1155 diagnostics
+ Found 1154 diagnostics

optuna (https://github.com/optuna/optuna)
- error[unsupported-operator] optuna/visualization/_timeline.py:63:13: Operator `-` is unsupported between objects of type `Unknown | datetime | None` and `datetime | None`
- error[unsupported-operator] tests/storages_tests/test_storages.py:328:13: Operator `<` is not supported for types `None` and `datetime`, in comparing `datetime | None` with `datetime`
- error[unsupported-operator] tests/storages_tests/test_storages.py:333:13: Operator `<` is not supported for types `datetime` and `None`, in comparing `datetime` with `datetime | None`
- error[unsupported-operator] tests/storages_tests/test_storages.py:333:36: Operator `<` is not supported for types `None` and `datetime`, in comparing `datetime | None` with `datetime`
- Found 963 diagnostics
+ Found 959 diagnostics

django-stubs (https://github.com/typeddjango/django-stubs)
- error[unresolved-attribute] tests/test_generic_consistency.py:27:29: Type `expr` has no attribute `id`
- Found 463 diagnostics
+ Found 462 diagnostics

mitmproxy (https://github.com/mitmproxy/mitmproxy)
- error[non-subscriptable] examples/contrib/portfile.py:29:38: Cannot subscript object of type `None` with no `__getitem__` method
- Found 1828 diagnostics
+ Found 1827 diagnostics

openlibrary (https://github.com/internetarchive/openlibrary)
- error[invalid-argument-type] openlibrary/catalog/marc/parse.py:523:28: Argument to function `read_author_person` is incorrect: Expected `MarcFieldBase`, found `str | MarcFieldBase`
- Found 718 diagnostics
+ Found 717 diagnostics

scikit-learn (https://github.com/scikit-learn/scikit-learn)
- warning[possibly-unbound-attribute] sklearn/linear_model/_least_angle.py:580:18: Attribute `dtype` on type `Unknown | None | (Unknown & ~None & ~Literal[False] & ~Literal["auto"] & ~Literal[True])` is possibly unbound
- Found 2295 diagnostics
+ Found 2294 diagnostics

sympy (https://github.com/sympy/sympy)
- error[unresolved-attribute] sympy/matrices/expressions/_shape.py:61:24: Type `Expr` has no attribute `shape`
- error[unresolved-attribute] sympy/testing/tests/test_code_quality.py:94:35: Type `expr` has no attribute `id`
- Found 17911 diagnostics
+ Found 17909 diagnostics