[ty] Add a new diagnostic to detect invalid class patterns in match statements by abhijeetbodas2001 · Pull Request #22939 · astral-sh/ruff (original) (raw)

added the ty

Multi-file analysis & type inference

label

Jan 29, 2026

abhijeetbodas2001 changed the title[ty] [DRAFT] new diagnostic called-match-pattern-must-be-a-type [ty] new diagnostic called-match-pattern-must-be-a-type

Feb 8, 2026

AlexWaygood changed the title[ty] new diagnostic called-match-pattern-must-be-a-type [ty] Add a new diagnostic to detect invalid class patterns in match statements

Feb 16, 2026

AlexWaygood added a commit that referenced this pull request

Feb 16, 2026

Summary

Any type type can only be inhabited by class objects; any type | <dynamic type> union could materialize to a class object; and any <class object> & <dynamic type> intersection is a subtype of a class object. So using a value that inhabits any of these types as a class pattern should not cause us to emit the invalid-match-pattern diagnostic.

This PR fixes several false positives that showed up in the ecosystem report in #22939

Test Plan

mdtests added

carljm added a commit that referenced this pull request

Feb 16, 2026

• main: (43 commits) [ruff] Suppress diagnostic for strings with backslashes in interpolations before Python 3.12 (RUF027) (#21069) [flake8-bugbear] Fix B023 false positive for immediately-invoked lambdas (#23294) [ty] Add Final mdtests for loops and redeclaration (#23331) [flake8-pyi] Also check string annotations (PYI041) (#19023) Remove AlexWaygood as a flake8-pyi codeowner (#23347) [ty] Add comments to clarify the purpose of NominalInstanceType::class_name and NominalInstanceType::class_module_name (#23339) Add attestations for release artifacts and Docker images (#23111) [ty] Fix assert_type diagnostic messages (#23342) [ty] Force-update all insta snapshots (#23343) Add Q004 to the list of conflicting rules (#23340) [ty] Fix invalid-match-pattern false positives (#23338) [ty] new diagnostic called-match-pattern-must-be-a-type (#22939) [ty] Update flaky projects (#23337) [ty] Increase timeout for ecosystem report to 40 min (#23336) Bump ecosystem-analyzer pin (#23335) [ty] Replace strsim with CPython-based Levenshtein implementation (#23291) [ty] Add mdtest for staticmethod assigned in class body (#23330) [ty] fix inferring type variable from string literal argument (#23326) [ty] bytes literal is a sequence of integers (#23329) Update rand and getrandom (#23333) ...

KotlinIsland pushed a commit to KotlinIsland/basedpython that referenced this pull request

May 1, 2026

Summary

Any type type can only be inhabited by class objects; any type | <dynamic type> union could materialize to a class object; and any <class object> & <dynamic type> intersection is a subtype of a class object. So using a value that inhabits any of these types as a class pattern should not cause us to emit the invalid-match-pattern diagnostic.

This PR fixes several false positives that showed up in the ecosystem report in astral-sh/ruff#22939

Test Plan

mdtests added

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