[Oleksandr Tarasiuk (a-tarasyuk)]

Fixes #65337

[Jake Bailey (jakebailey)]

If you're willing, this would be much easier to review if it were two commits, one that adds the test and baselines showing bad behavior, then one commit with the fix and baseline update showing it works.

[Copilot]

🟢 Approval recommended

No active review issues are reported for the accessor metadata fallback change.

No open issues 🎉

What changed in this PR

Fixes #65337 by restoring TypeScript 6.0 behavior in the native compiler: accessor design:type metadata uses the getter’s annotation when the setter parameter is unannotated.

Changes:

• Fall back to the getter annotation while preserving explicit setter annotation precedence.
• Add coverage for accessor order, decorator placement, getter-only accessors, explicit any, and static accessors.
• Update JavaScript, type, and symbol baselines.

File	Description
tsc/​testdata/​tests/​cases/​conformance/​decorators/​class/​accessor/​decoratorOnClassAccessor8.ts	Adds accessor metadata regression cases.
tsc/​testdata/​baselines/​reference/​conformance/​decoratorOnClassAccessor8(target=es2015).types	Records types for the added cases.
tsc/​testdata/​baselines/​reference/​conformance/​decoratorOnClassAccessor8(target=es2015).symbols	Records symbols for the added cases.
tsc/​testdata/​baselines/​reference/​conformance/​decoratorOnClassAccessor8(target=es2015).js	Captures corrected metadata while preserving parameter metadata.
tsc/​internal/​transformers/​tstransforms/​typeserializer.go	Falls back to the getter when the setter has no annotation.

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

No active review issues are identified for the accessor decorator metadata fallback change.

No open issues 🎉

_{Review effort: Balanced}