[ty] Simplify TypeVar assignability/subtyping logic#24138
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AlexWaygood merged 1 commit intomainfrom Mar 23, 2026
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Consolidate two separate match branches for `(_, Type::TypeVar)` when the typevar is inferable into a single branch. The old code duplicated the upper-bound check between the match guard and the body, with fallthrough to a catch-all returning `self.never()`. Since `when_none_or` naturally returns `always` for no bound and the check result otherwise (with `never` matching the fallthrough behavior), the two branches can be merged. https://claude.ai/code/session_016rAtEXYhnAGFW3ok4xARvQ
Typing conformance resultsNo changes detected ✅Current numbersThe percentage of diagnostics emitted that were expected errors held steady at 85.38%. The percentage of expected errors that received a diagnostic held steady at 78.70%. The number of fully passing files held steady at 64/132. |
Memory usage reportMemory usage unchanged ✅ |
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| Lint rule | Added | Removed | Changed |
|---|---|---|---|
invalid-await |
0 | 40 | 0 |
invalid-return-type |
0 | 1 | 0 |
| Total | 0 | 41 | 0 |
Changes in flaky projects detected. Raw diff output excludes flaky projects; see the HTML report for details.
carljm
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Mar 25, 2026
* main: (36 commits) [ty] Reduce diagnostic range for `invalid-metaclass` (#24145) [ty] Simplify TypeVar assignability/subtyping logic (#24138) [ty] Prevent tainted loop bindings in cycle normalization (#24143) [ty] Add precisely-typed overloads for `TypedDict` update (#24101) [ty] Fix folding ranges of comments separated by statements (#24132) Bump ecosystem-analyzer pin (#24136) Bump ecosystem-analyzer pin (#24135) Simplify `NewType` handling in `relation.rs` (#24109) [ty] Add more tests for `NewType` subtyping (#24115) [ty] Add `NewType`s to the property tests (#24113) [ty] Prepare test files for unreachable code change (#24133) `analyze graph`: resolve string imports that reference attributes, not just modules (#24058) Update Artifact GitHub Actions dependencies (#24116) Update taiki-e/install-action action to v2.68.33 (#24130) Update taiki-e/install-action action to v2.68.32 (#24123) Update Rust crate serde_with to v3.18.0 (#24126) Update Swatinem/rust-cache action to v2.9.1 (#24127) Update Rust crate quick-junit to 0.6.0 (#24125) Update Rust crate clap to v4.6.0 (#24124) Update Rust crate tracing-subscriber to v0.3.23 (#24122) ...
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Summary
Refactor the TypeVar type relation checking logic to simplify the control flow and eliminate redundant conditions. The change consolidates two separate match arms that handled inferable TypeVars into a single arm with conditional logic based on whether the relation is an assignability check.
Test Plan
Existing tests