fix: handle accessors in declaration return types

[neallin917]

Summary

• handle bodyless accessors without entering a nested parameter-list lexical environment
• continue transforming import types in getter and setter annotations
• add explicit regression coverage for the TypeScript 5.9 declaration-emit crash

Root cause

TypeScript 5.9 suspends the surrounding lexical environment while visiting a function return type. Calling visitEachChild for an accessor nested in that type attempts to start another lexical environment and triggers Debug Failure. False expression: Lexical environment is suspended. This is tracked upstream in microsoft/TypeScript#58020.

The transformer now updates bodyless accessors directly while still visiting their type annotations and parameters.

Fixes #437

Validation

• yarn fmt:check
• yarn lint
• yarn build
• full test suite on Node.js 22: 52 passed, 0 failed, 1 skipped

AI assistance disclosure

OpenAI Codex was used to investigate the issue, draft the implementation and regression coverage, and run the validation commands listed above.

[danielpza]

Hello @neallin917, can you add some tests to validate the fix.

Also, please when using AI it would be nice to add a disclosure.

[neallin917]

Thanks for the feedback. I added a named regression test in 63fc37d that verifies the TypeScript 5.9 declaration emit completes and that getter/setter import type paths are rewritten.

I also added an AI-assistance disclosure to the PR description.

Validation:

• yarn fmt:check
• yarn lint
• yarn build
• yarn test (52 passed, 0 failed, 1 skipped)