[ty] fix panic when instantiating a type variable with invalid constraints#21663
Merged
carljm merged 3 commits intoastral-sh:mainfrom Dec 5, 2025
Merged
[ty] fix panic when instantiating a type variable with invalid constraints#21663carljm merged 3 commits intoastral-sh:mainfrom
carljm merged 3 commits intoastral-sh:mainfrom
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Diagnostic diff on typing conformance testsNo changes detected when running ty on typing conformance tests ✅ |
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mtshiba
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AlexWaygood,
carljm,
dcreager and
sharkdp
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carljm
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This looks good; sorry I didn't get to it sooner. Can you fix up the conflicts?
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Author
Yes, but it would be better to merge #21802 first. |
Contributor
Done |
carljm
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Dec 5, 2025
dcreager
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Dec 5, 2025
* origin/main: (41 commits) [ty] Carry generic context through when converting class into `Callable` (#21798) [ty] Add more tests for renamings (#21810) [ty] Minor improvements to `assert_type` diagnostics (#21811) [ty] Add some attribute/method renaming test cases (#21809) Update mkdocs-material to 9.7.0 (Insiders now free) (#21797) Remove unused whitespaces in test cases (#21806) [ty] fix panic when instantiating a type variable with invalid constraints (#21663) [ty] fix build failure caused by conflicts between #21683 and #21800 (#21802) [ty] do nothing with `store_expression_type` if `inner_expression_inference_state` is `Get` (#21718) [ty] increase the limit on the number of elements in a non-recursively defined literal union (#21683) [ty] normalize typevar bounds/constraints in cycles (#21800) [ty] Update completion eval to include modules [ty] Add modules to auto-import [ty] Add support for module-only import requests [ty] Refactor auto-import symbol info [ty] Clarify the use of `SymbolKind` in auto-import [ty] Redact ranking of completions from e2e LSP tests [ty] Tweaks tests to use clearer language [ty] Update evaluation results [ty] Make auto-import ignore symbols in modules starting with a `_` ...
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Summary
This PR fixes a panic that occurs with code like this:
The panic occurs because the constraints of
Tare inferred to beUnknown | Unknown.Calling
to_instanceon such a type results inUnknown, but the panic occurs because contexts expecting constraints on type variables only accept union types.A fundamental solution to this problem would be to define a new struct
TypeVarConstraintsto hold each constraint individually, rather than trying to store everything in aUnionType. There may be additional cost for converting between this and a union type. I'll ask codspeed if this is actually costly.Panic log
Test Plan
New corpus test