[ty] Add assertions to ensure that we never call KnownClass::Tuple.to_instance() or similar#21027
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AlexWaygood merged 1 commit intomainfrom Oct 22, 2025
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[ty] Add assertions to ensure that we never call KnownClass::Tuple.to_instance() or similar#21027AlexWaygood merged 1 commit intomainfrom
KnownClass::Tuple.to_instance() or similar#21027AlexWaygood merged 1 commit intomainfrom
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Diagnostic diff on typing conformance testsNo changes detected when running ty on typing conformance tests ✅ |
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* main: (65 commits) [ty] Some more simplifications when rendering constraint sets (#21009) [ty] Make `attributes.md` mdtests faster (#21030) [ty] Set `INSTA_FORCE_PASS` and `INSTA_OUTPUT` environment variables from mdtest.py (#21029) [ty] Fall back to `Divergent` for deeply nested specializations (#20988) [`ruff`] Autogenerate TypeParam nodes (#21028) [ty] Add assertions to ensure that we never call `KnownClass::Tuple.to_instance()` or similar (#21027) [`ruff`] Auto generate ast Pattern nodes (#21024) [`flake8-simplify`] Skip `SIM911` when unknown arguments are present (#20697) Render a diagnostic for syntax errors introduced in formatter tests (#21021) [ty] Support goto-definition on vendored typeshed stubs (#21020) [ty] Implement go-to for binary and unary operators (#21001) [ty] Avoid ever-growing default types (#20991) [syntax-errors] Name is parameter and global (#20426) [ty] Disable panicking mdtest (#21016) [ty] Fix completions at end of file (#20993) [ty] Fix out-of-order semantic token for function with regular argument after kwargs (#21013) [ty] Fix auto import for files with `from __future__` import (#20987) [`fastapi`] Handle ellipsis defaults in FAST002 autofix (`FAST002`) (#20810) [`ruff`] Skip autofix for keyword and `__debug__` path params (#20960) [`flake8-bugbear`] Skip `B905` and `B912` if <2 iterables and no starred arguments (#20998) ...
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Summary
This came up in #20988. It's usually a mistake to call
KnownClass::Tuple.to_instance(); it will usually be more efficient and more correct to callType::homogeneous_tuple()orType::heterogeneous_tuple()instead. Add some debug assertions to ensure that we don't make this mistake.I considered making these non-debug assertions, as the equality check should be pretty cheap, but
KnownClass::to_instance()is a pretty hot method, and I think it's exceedingly likely that debug assertions will catch this bug cropping up in the future.I also removed the private helper method
Type::non_tuple_instance()frominstance.rs. It wasn't a zero-cost abstraction, it didn't save that much code, and it had to have a big warning doc-comment above it telling us never to make it public to code outside the module. All things considered, it was no longer worth it to keep it around.Test Plan
cargo test -p ty_python_semantic