From be7e2efad0b11892214201996578920f6b41e123 Mon Sep 17 00:00:00 2001
From: Yuta Saito <kateinoigakukun@gmail.com>
Date: Mon, 26 Jan 2026 18:05:22 +0900
Subject: [PATCH] =?UTF-8?q?-=20Updated=20`@JSClass`=20macro=20to=20emit=20?=
 =?UTF-8?q?an=20error=20unless=20it=E2=80=99s=20attached=20to=20a=20`struc?=
 =?UTF-8?q?t`=20(`Plugins/BridgeJS/Sources/BridgeJSMacros/JSClassMacro.swi?=
 =?UTF-8?q?ft:13`).=20-=20Added=20new=20diagnostic=20message=20`@JSClass?=
 =?UTF-8?q?=20can=20only=20be=20applied=20to=20structs.`=20(`Plugins/Bridg?=
 =?UTF-8?q?eJS/Sources/BridgeJSMacros/JSMacroSupport.swift:8`).=20-=20Upda?=
 =?UTF-8?q?ted=20macro=20expansion=20tests=20so=20`class`/`enum`/`actor`?=
 =?UTF-8?q?=20usages=20now=20produce=20diagnostics=20and=20no=20generated?=
 =?UTF-8?q?=20members/extensions=20(`Plugins/BridgeJS/Tests/BridgeJSMacros?=
 =?UTF-8?q?Tests/JSClassMacroTests.swift:147`).=20-=20Verified=20with=20`s?=
 =?UTF-8?q?wift=20test=20--package-path=20./Plugins/BridgeJS=20--filter=20?=
 =?UTF-8?q?BridgeJSMacrosTests`.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../Sources/BridgeJSMacros/JSClassMacro.swift |  8 ++++
 .../BridgeJSMacros/JSMacroSupport.swift       |  1 +
 .../JSClassMacroTests.swift                   | 45 +++++++++----------
 3 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/Plugins/BridgeJS/Sources/BridgeJSMacros/JSClassMacro.swift b/Plugins/BridgeJS/Sources/BridgeJSMacros/JSClassMacro.swift
index 060d2269b..8a3f83f05 100644
--- a/Plugins/BridgeJS/Sources/BridgeJSMacros/JSClassMacro.swift
+++ b/Plugins/BridgeJS/Sources/BridgeJSMacros/JSClassMacro.swift
@@ -12,6 +12,13 @@ extension JSClassMacro: MemberMacro {
         conformingTo protocols: [TypeSyntax],
         in context: some MacroExpansionContext
     ) throws -> [DeclSyntax] {
+        guard declaration.is(StructDeclSyntax.self) else {
+            context.diagnose(
+                Diagnostic(node: Syntax(declaration), message: JSMacroMessage.unsupportedJSClassDeclaration)
+            )
+            return []
+        }
+
         var members: [DeclSyntax] = []
 
         let existingMembers = declaration.memberBlock.members
@@ -59,6 +66,7 @@ extension JSClassMacro: ExtensionMacro {
         conformingTo protocols: [TypeSyntax],
         in context: some MacroExpansionContext
     ) throws -> [ExtensionDeclSyntax] {
+        guard declaration.is(StructDeclSyntax.self) else { return [] }
         guard !protocols.isEmpty else { return [] }
 
         let conformanceList = protocols.map { $0.trimmed.description }.joined(separator: ", ")
diff --git a/Plugins/BridgeJS/Sources/BridgeJSMacros/JSMacroSupport.swift b/Plugins/BridgeJS/Sources/BridgeJSMacros/JSMacroSupport.swift
index b10871f6a..59fa1c4c2 100644
--- a/Plugins/BridgeJS/Sources/BridgeJSMacros/JSMacroSupport.swift
+++ b/Plugins/BridgeJS/Sources/BridgeJSMacros/JSMacroSupport.swift
@@ -5,6 +5,7 @@ import SwiftDiagnostics
 
 enum JSMacroMessage: String, DiagnosticMessage {
     case unsupportedDeclaration = "@JSFunction can only be applied to functions or initializers."
+    case unsupportedJSClassDeclaration = "@JSClass can only be applied to structs."
     case unsupportedVariable = "@JSGetter can only be applied to single-variable declarations."
     case unsupportedSetterDeclaration = "@JSSetter can only be applied to functions."
     case invalidSetterName =
diff --git a/Plugins/BridgeJS/Tests/BridgeJSMacrosTests/JSClassMacroTests.swift b/Plugins/BridgeJS/Tests/BridgeJSMacrosTests/JSClassMacroTests.swift
index 95e3893ed..b27b93941 100644
--- a/Plugins/BridgeJS/Tests/BridgeJSMacrosTests/JSClassMacroTests.swift
+++ b/Plugins/BridgeJS/Tests/BridgeJSMacrosTests/JSClassMacroTests.swift
@@ -153,16 +153,15 @@ import BridgeJSMacros
             """,
             expandedSource: """
                 class MyClass {
-                    let jsObject: JSObject
-
-                    init(unsafelyWrapping jsObject: JSObject) {
-                        self.jsObject = jsObject
-                    }
-                }
-
-                extension MyClass: _JSBridgedClass {
                 }
                 """,
+            diagnostics: [
+                DiagnosticSpec(
+                    message: "@JSClass can only be applied to structs.",
+                    line: 1,
+                    column: 1
+                )
+            ],
             macroSpecs: macroSpecs,
             indentationWidth: indentationWidth
         )
@@ -177,16 +176,15 @@ import BridgeJSMacros
             """,
             expandedSource: """
                 enum MyEnum {
-                    let jsObject: JSObject
-
-                    init(unsafelyWrapping jsObject: JSObject) {
-                        self.jsObject = jsObject
-                    }
-                }
-
-                extension MyEnum: _JSBridgedClass {
                 }
                 """,
+            diagnostics: [
+                DiagnosticSpec(
+                    message: "@JSClass can only be applied to structs.",
+                    line: 1,
+                    column: 1
+                )
+            ],
             macroSpecs: macroSpecs,
             indentationWidth: indentationWidth
         )
@@ -201,16 +199,15 @@ import BridgeJSMacros
             """,
             expandedSource: """
                 actor MyActor {
-                    let jsObject: JSObject
-
-                    init(unsafelyWrapping jsObject: JSObject) {
-                        self.jsObject = jsObject
-                    }
-                }
-
-                extension MyActor: _JSBridgedClass {
                 }
                 """,
+            diagnostics: [
+                DiagnosticSpec(
+                    message: "@JSClass can only be applied to structs.",
+                    line: 1,
+                    column: 1
+                )
+            ],
             macroSpecs: macroSpecs,
             indentationWidth: indentationWidth
         )