[Cheng (chengchuu)]

Summary

Fixes #64666

Prevent declaration emit from crashing when an exported interface extends a labeled interface. Recognize heritage type references as diagnostic contexts and reuse the existing interface extends and class implements diagnostics.

Regression tests cover both clauses and an inaccessible type argument.

Reproduction

The standalone reproduction prints panic: Diagnostic emitted without context and exits 2. The compiler should report diagnostics for the invalid input without crashing.

Validation

I manually ran the following checks from the repository root on macOS ARM64. All passed:

GOWORK=off go -C tsc test -mod=readonly ./internal/testrunner \
  -run 'TestLocal/declarationEmitInaccessibleHeritageType' -count=1
npx hereby test
npx hereby lint
npx hereby check:format

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🔵 Needs a closer look

Class-expression heritage bases are not fully handled and may still produce incorrect diagnostics.

No open issues 🎉

_{Review effort: Lite}