[SwiftLexicalLookup] Add ScopeSyntax conformance for EnumCaseDeclSyntax#3280
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Ronitsabhaya75 wants to merge 1 commit intoswiftlang:mainfrom
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[SwiftLexicalLookup] Add ScopeSyntax conformance for EnumCaseDeclSyntax#3280Ronitsabhaya75 wants to merge 1 commit intoswiftlang:mainfrom
Ronitsabhaya75 wants to merge 1 commit intoswiftlang:mainfrom
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Ronitsabhaya75
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rintaro
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rintaro
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Feb 23, 2026
| /// of subsequent parameters within the same case element, e.g.: | ||
| /// ```swift | ||
| /// enum E { | ||
| /// case foo(x: Int, y: Int = x) // `x` visible in `y`'s default |
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Is this true? As far as I tried, x is not visible from the default value of y. Am I missing anything?
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This PR adds
ScopeSyntaxconformance toEnumCaseDeclSyntaxso that name lookup actually works for enum case payloads.Previously, associated-value parameter names were totally invisible to lookup. I just set it up so a parameter is only in scope for the default-value expressions of parameters that come after it in the same case. It doesn't leak into other cases (e.g.
case foo(a: Int), bar(b: Int = a)won't resolvea) and isn't visible outside the enum case declaration at all.I also added
EnumCaseParameterSyntax: IdentifiableSyntaxusing the same logic asFunctionParameterSyntax, and threw in a few tests to cover the basic forward references and isolation behavior.Let me know if this approach makes sense or if I should add more tests!