[good-first-issue] Checker: validate signal extends compatibility · Checker: signal extends 호환성 검증

[github-actions]

[good-first-issue] Checker: validate signal extends compatibility · Checker: signal extends 호환성 검증

Labels: good first issue, help wanted, feature, area:dsl-compiler, priority:medium

---

Goal · 목표

Add signal extends chain support to membrane compatibility checks in checker.ts.

checker.ts에 signal extends 관계를 반영한 막 호환 검사를 추가합니다.

Tasks · 작업

• Build extends chain when collecting SignalDecl · SignalDecl 수집 시 extends 체인 구축
• Verify membrane accepts accepts supertype signals (spec §11) · membrane accepts 상위 타입 수용 검증

References · 참고

• language-specification.html — signal extends, structural typing

Definition of done · 완료 기준

Checker recognizes subtype signals for accepts validation per spec §11.

하위 신호가 상위를 accepts하는 막에 전달 가능함을 checker가 인지.

[github-actions]

Partially completed on main: finalizeSignals(), signalsCompatible(), tests in compile.test.ts. Remaining: structural field compatibility, priority inheritance. See .github/issue-drafts/09-checker-signal-extends.md.