[Python] Fix type var scoping for PEP 695 annotations#4362
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Prevent generic type params from leaking outside their function scope: - Emit `Any` for type vars outside function type param scope (e.g., class fields, variable annotations) instead of referencing undefined type vars - Only add actually-declared (repeated) generic params to ScopedTypeParams, so non-repeated params erased to Any don't leak - Remove test_mailbox_processor.py from pyright CI exclude list (now passes) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Python Type Checking Results (Pyright)
Excluded files with errors (4 files)These files have known type errors and are excluded from CI. Remove from
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Revert to using getGenericTypeParams for ScopedTypeParams so that all
outer function type params are tracked, preventing inner functions from
re-declaring them in PEP 695 syntax ("TypeVar X is already in use by
an outer scope"). The annotation change (emit Any outside function
scope) is kept as that was the actual fix for the mailbox_processor issue.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Two-part fix for PEP 695 type var scoping: 1. In transformFunction, only add repeated (actually-declared) generic params to ScopedTypeParams. Non-repeated params erased to Any must not enter scope, or inner functions will emit undefined type var references (e.g., Async[_A] where _A is never declared). 2. In transformModuleFunction, compute the declared type params (explicit generics + signature generics) BEFORE transforming the body and add them to ScopedTypeParams. This prevents inner functions from re-declaring type vars that the outer function already declares in its PEP 695 [] syntax. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
Anyfor type vars outside function type param scope (e.g., class fields, variable annotations) instead of referencing undefined type varsScopedTypeParams, so non-repeated params erased toAnydon't leaktest_mailbox_processor.pyfrom pyright CI exclude list (now passes)Test plan
./build.sh test pythonto verify no regressionstest_mailbox_processor.pypasses🤖 Generated with Claude Code