BridgeJS: Fix macro test suites silently ignoring failures

Plugins/BridgeJS/Package.swift

@@ -72,7 +72,7 @@ let package = Package(
             name: "BridgeJSMacrosTests",
             dependencies: [
                 "BridgeJSMacros",
-                .product(name: "SwiftSyntaxMacrosTestSupport", package: "swift-syntax"),
+                .product(name: "SwiftSyntaxMacrosGenericTestSupport", package: "swift-syntax"),
             ]
         ),
 

Plugins/BridgeJS/Sources/BridgeJSMacros/JSClassMacro.swift

@@ -66,9 +66,16 @@ extension JSClassMacro: ExtensionMacro {
         conformingTo protocols: [TypeSyntax],
         in context: some MacroExpansionContext
     ) throws -> [ExtensionDeclSyntax] {
-        guard declaration.is(StructDeclSyntax.self) else { return [] }
+        guard let structDecl = declaration.as(StructDeclSyntax.self) else { return [] }
         guard !protocols.isEmpty else { return [] }
 
+        // Do not add extension if the struct already conforms to _JSBridgedClass
+        if let clause = structDecl.inheritanceClause,
+            clause.inheritedTypes.contains(where: { $0.type.trimmed.description == "_JSBridgedClass" })
+        {
+            return []
+        }
+
         let conformanceList = protocols.map { $0.trimmed.description }.joined(separator: ", ")
         return [
             try ExtensionDeclSyntax("extension \(type.trimmed): \(raw: conformanceList) {}")

Plugins/BridgeJS/Sources/BridgeJSMacros/JSFunctionMacro.swift

@@ -47,7 +47,7 @@ extension JSFunctionMacro: BodyMacro {
                 context.diagnose(
                     Diagnostic(node: Syntax(declaration), message: JSMacroMessage.unsupportedDeclaration)
                 )
-                return []
+                return [CodeBlockItemSyntax(stringLiteral: "fatalError(\"@JSFunction init must be inside a type\")")]
             }
 
             let glueName = JSMacroHelper.glueName(baseName: "init", enclosingTypeName: enclosingTypeName)
@@ -70,3 +70,19 @@ extension JSFunctionMacro: BodyMacro {
         return []
     }
 }
+
+extension JSFunctionMacro: PeerMacro {
+    /// Emits a diagnostic when @JSFunction is applied to a declaration that is not a function or initializer.
+    /// BodyMacro is only invoked for declarations with optional code blocks (e.g. functions, initializers),
+    /// so for vars and other decls we need PeerMacro to run and diagnose.
+    public static func expansion(
+        of node: AttributeSyntax,
+        providingPeersOf declaration: some DeclSyntaxProtocol,
+        in context: some MacroExpansionContext
+    ) throws -> [DeclSyntax] {
+        if declaration.is(FunctionDeclSyntax.self) { return [] }
+        if declaration.is(InitializerDeclSyntax.self) { return [] }
+        context.diagnose(Diagnostic(node: Syntax(declaration), message: JSMacroMessage.unsupportedDeclaration))
+        return []
+    }
+}

Plugins/BridgeJS/Sources/BridgeJSMacros/JSGetterMacro.swift

@@ -60,3 +60,20 @@ extension JSGetterMacro: AccessorMacro {
         ]
     }
 }
+
+extension JSGetterMacro: PeerMacro {
+    /// Emits a diagnostic when @JSGetter is applied to a declaration that is not a variable (e.g. a function).
+    /// AccessorMacro may not be invoked for non-property declarations. For variables with multiple
+    /// bindings, the compiler emits its own diagnostic; we only diagnose non-variable decls here.
+    public static func expansion(
+        of node: AttributeSyntax,
+        providingPeersOf declaration: some DeclSyntaxProtocol,
+        in context: some MacroExpansionContext
+    ) throws -> [DeclSyntax] {
+        guard declaration.is(VariableDeclSyntax.self) else {
+            context.diagnose(Diagnostic(node: Syntax(declaration), message: JSMacroMessage.unsupportedVariable))
+            return []
+        }
+        return []
+    }
+}

Plugins/BridgeJS/Sources/BridgeJSMacros/JSSetterMacro.swift

@@ -25,13 +25,23 @@ extension JSSetterMacro: BodyMacro {
         let rawFunctionName = JSMacroHelper.stripBackticks(functionName)
         guard rawFunctionName.hasPrefix("set"), rawFunctionName.count > 3 else {
             context.diagnose(Diagnostic(node: Syntax(declaration), message: JSMacroMessage.invalidSetterName))
-            return []
+            return [
+                CodeBlockItemSyntax(
+                    stringLiteral:
+                        "fatalError(\"@JSSetter function name must start with 'set' followed by a property name\")"
+                )
+            ]
         }
 
         let propertyName = String(rawFunctionName.dropFirst(3))
         guard !propertyName.isEmpty else {
             context.diagnose(Diagnostic(node: Syntax(declaration), message: JSMacroMessage.invalidSetterName))
-            return []
+            return [
+                CodeBlockItemSyntax(
+                    stringLiteral:
+                        "fatalError(\"@JSSetter function name must start with 'set' followed by a property name\")"
+                )
+            ]
         }
 
         // Convert first character to lowercase (e.g., "Foo" -> "foo")
@@ -56,7 +66,11 @@ extension JSSetterMacro: BodyMacro {
         let parameters = functionDecl.signature.parameterClause.parameters
         guard let firstParam = parameters.first else {
             context.diagnose(Diagnostic(node: Syntax(declaration), message: JSMacroMessage.setterRequiresParameter))
-            return []
+            return [
+                CodeBlockItemSyntax(
+                    stringLiteral: "fatalError(\"@JSSetter function must have at least one parameter\")"
+                )
+            ]
         }
 
         let paramName = firstParam.secondName ?? firstParam.firstName
@@ -69,3 +83,21 @@ extension JSSetterMacro: BodyMacro {
         return [CodeBlockItemSyntax(stringLiteral: "try \(call)")]
     }
 }
+
+extension JSSetterMacro: PeerMacro {
+    /// Emits a diagnostic when @JSSetter is applied to a declaration that is not a function.
+    /// BodyMacro is only invoked for declarations with optional code blocks (e.g. functions).
+    public static func expansion(
+        of node: AttributeSyntax,
+        providingPeersOf declaration: some DeclSyntaxProtocol,
+        in context: some MacroExpansionContext
+    ) throws -> [DeclSyntax] {
+        guard declaration.is(FunctionDeclSyntax.self) else {
+            context.diagnose(
+                Diagnostic(node: Syntax(declaration), message: JSMacroMessage.unsupportedSetterDeclaration)
+            )
+            return []
+        }
+        return []
+    }
+}

Plugins/BridgeJS/Tests/BridgeJSMacrosTests/JSClassMacroTests.swift

@@ -1,8 +1,7 @@
 import SwiftDiagnostics
 import SwiftSyntax
 import SwiftSyntaxMacroExpansion
-import SwiftSyntaxMacros
-import SwiftSyntaxMacrosTestSupport
+import SwiftSyntaxMacrosGenericTestSupport
 import Testing
 import BridgeJSMacros
 
@@ -13,14 +12,15 @@ import BridgeJSMacros
     ]
 
     @Test func emptyStruct() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             struct MyClass {
             }
             """,
             expandedSource: """
                 struct MyClass {
+
                     let jsObject: JSObject
 
                     init(unsafelyWrapping jsObject: JSObject) {
@@ -32,12 +32,12 @@ import BridgeJSMacros
                 }
                 """,
             macroSpecs: macroSpecs,
-            indentationWidth: indentationWidth
+            indentationWidth: indentationWidth,
         )
     }
 
     @Test func structWithExistingJSObject() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             struct MyClass {
@@ -62,7 +62,7 @@ import BridgeJSMacros
     }
 
     @Test func structWithExistingInit() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             struct MyClass {
@@ -73,11 +73,11 @@ import BridgeJSMacros
             """,
             expandedSource: """
                 struct MyClass {
-                    let jsObject: JSObject
-
                     init(unsafelyWrapping jsObject: JSObject) {
                         self.jsObject = jsObject
                     }
+
+                    let jsObject: JSObject
                 }
 
                 extension MyClass: _JSBridgedClass {
@@ -89,7 +89,7 @@ import BridgeJSMacros
     }
 
     @Test func structWithBothExisting() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             struct MyClass {
@@ -118,7 +118,7 @@ import BridgeJSMacros
     }
 
     @Test func structWithMembers() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             struct MyClass {
@@ -127,10 +127,10 @@ import BridgeJSMacros
             """,
             expandedSource: """
                 struct MyClass {
-                    let jsObject: JSObject
-
                     var name: String
 
+                    let jsObject: JSObject
+
                     init(unsafelyWrapping jsObject: JSObject) {
                         self.jsObject = jsObject
                     }
@@ -145,7 +145,7 @@ import BridgeJSMacros
     }
 
     @Test func _class() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             class MyClass {
@@ -168,7 +168,7 @@ import BridgeJSMacros
     }
 
     @Test func _enum() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             enum MyEnum {
@@ -191,7 +191,7 @@ import BridgeJSMacros
     }
 
     @Test func _actor() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             actor MyActor {
@@ -214,7 +214,7 @@ import BridgeJSMacros
     }
 
     @Test func structWithDifferentJSObjectName() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             struct MyClass {
@@ -223,10 +223,10 @@ import BridgeJSMacros
             """,
             expandedSource: """
                 struct MyClass {
-                    let jsObject: JSObject
-
                     var otherProperty: String
 
+                    let jsObject: JSObject
+
                     init(unsafelyWrapping jsObject: JSObject) {
                         self.jsObject = jsObject
                     }
@@ -241,7 +241,7 @@ import BridgeJSMacros
     }
 
     @Test func structWithDifferentInit() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             struct MyClass {
@@ -251,11 +251,11 @@ import BridgeJSMacros
             """,
             expandedSource: """
                 struct MyClass {
-                    let jsObject: JSObject
-
                     init(name: String) {
                     }
 
+                    let jsObject: JSObject
+
                     init(unsafelyWrapping jsObject: JSObject) {
                         self.jsObject = jsObject
                     }
@@ -270,7 +270,7 @@ import BridgeJSMacros
     }
 
     @Test func structWithMultipleMembers() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             struct MyClass {
@@ -280,11 +280,11 @@ import BridgeJSMacros
             """,
             expandedSource: """
                 struct MyClass {
-                    let jsObject: JSObject
-
                     var name: String
                     var age: Int
 
+                    let jsObject: JSObject
+
                     init(unsafelyWrapping jsObject: JSObject) {
                         self.jsObject = jsObject
                     }
@@ -299,7 +299,7 @@ import BridgeJSMacros
     }
 
     @Test func structWithComment() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             /// Documentation comment
             @JSClass
@@ -309,6 +309,7 @@ import BridgeJSMacros
             expandedSource: """
                 /// Documentation comment
                 struct MyClass {
+
                     let jsObject: JSObject
 
                     init(unsafelyWrapping jsObject: JSObject) {
@@ -325,14 +326,15 @@ import BridgeJSMacros
     }
 
     @Test func structAlreadyConforms() {
-        assertMacroExpansion(
+        TestSupport.assertMacroExpansion(
             """
             @JSClass
             struct MyClass: _JSBridgedClass {
             }
             """,
             expandedSource: """
                 struct MyClass: _JSBridgedClass {
+
                     let jsObject: JSObject
 
                     init(unsafelyWrapping jsObject: JSObject) {