More @available's so warnings don't show up in generated code

Generator/Sources/CodeWriters/Swift/SyntaxWriters/SourceFile.swift

@@ -24,13 +24,15 @@ public struct SwiftSourceFileWriter: SwiftDeclarationWriter {
     }
 
     public func writeExtension(
+        attributes: [SwiftAttribute] = [],
         type: SwiftType,
         protocolConformances: [SwiftType] = [],
         whereClauses: [String] = [],
         members: (SwiftTypeDefinitionWriter) throws -> Void) rethrows {
 
         var output = output
         output.beginLine(group: .alone)
+        writeAttributes(attributes)
         output.write("extension ")
         type.write(to: &output)
         writeInheritanceClause(protocolConformances)

Generator/Sources/ProjectionModel/Projection+conversion.swift

@@ -83,6 +83,16 @@ extension Projection {
             : definitionBindingType.member(try Projection.toBindingInstantiationTypeName(genericArgs: type.genericArgs))
     }
 
+    public static func getAvailableAttribute(
+            _ attributable: any Attributable,
+            deprecator: (any Attributable)? = nil) throws -> SwiftAttribute? {
+        guard let deprecatedAttribute = try attributable.findAttribute(WindowsMetadata.DeprecatedAttribute.self)
+                ?? deprecator?.findAttribute(WindowsMetadata.DeprecatedAttribute.self) else { return nil }
+        // DeprecatedAttribute tells us the ContractVersion in which an attribute was deprecated,
+        // but since apps should run on any future OS version, we can mark it as unconditionally deprecated.
+        return SwiftAttribute("available(*, deprecated, message: \"\(deprecatedAttribute.message)\")")
+    }
+
     public static func getAttributes(
             _ attributable: any Attributable,
             deprecator: (any Attributable)? = nil) throws -> [SwiftAttribute] {
@@ -99,11 +109,8 @@ extension Projection {
             }
 
         // Also add deprecation attributes
-        if let deprecatedAttribute = try attributable.findAttribute(WindowsMetadata.DeprecatedAttribute.self)
-                ?? deprecator?.findAttribute(WindowsMetadata.DeprecatedAttribute.self) {
-            // DeprecatedAttribute tells us the ContractVersion in which an attribute was deprecated,
-            // but since apps should run on any future OS version, we can mark it as unconditionally deprecated.
-            attributes.append(SwiftAttribute("available(*, deprecated, message: \"\(deprecatedAttribute.message)\")"))
+        if let availableAttribute = try getAvailableAttribute(attributable, deprecator: deprecator) {
+            attributes.append(availableAttribute)
         }
 
         return attributes

Generator/Sources/SwiftWinRT/Writing/ABIBinding.swift

@@ -28,18 +28,7 @@ internal func writeABIBindingConformance(_ typeDefinition: TypeDefinition, gener
 
     if let enumDefinition = typeDefinition as? EnumDefinition {
         assert(genericArgs == nil)
-        let enumBindingProtocol = try projection.isSwiftEnumEligible(enumDefinition)
-            ? SupportModules.WinRT.closedEnumBinding : SupportModules.WinRT.openEnumBinding
-        try writer.writeExtension(
-                type: projection.toTypeReference(enumDefinition.bindType()),
-                protocolConformances: [ enumBindingProtocol ]) { writer in
-            // public static var typeName: String { "..." }
-            try writeTypeNameProperty(type: enumDefinition.bindType(), to: writer)
-
-            // public static var ireferenceID: COM.COMInterfaceID { .init(...) }
-            // public static var ireferenceArrayID: COM.COMInterfaceID { .init(...) }
-            try writeIReferenceIDProperties(boxableType: enumDefinition.bindType(), to: writer)
-        }
+        try writeEnumBindingExtension(enumDefinition, projection: projection, to: writer)
         return
     }
 
@@ -69,6 +58,7 @@ internal func writeABIBindingConformance(_ typeDefinition: TypeDefinition, gener
         //     internal final class Boolean: WinRTBinding... {}
         // }
         try writer.writeExtension(
+                attributes: [ Projection.getAvailableAttribute(typeDefinition) ].compactMap { $0 },
                 type: projection.toBindingType(typeDefinition)) { writer in
             try writeInterfaceOrDelegateBindingType(
                 typeDefinition.bindType(genericArgs: genericArgs),
@@ -80,11 +70,32 @@ internal func writeABIBindingConformance(_ typeDefinition: TypeDefinition, gener
         // Generic type definition. Create a namespace for projections of specializations.
         // public enum IVectorBinding {}
         try writer.writeEnum(
+            attributes: [ Projection.getAvailableAttribute(typeDefinition) ].compactMap { $0 },
             visibility: Projection.toVisibility(typeDefinition.visibility),
             name: projection.toBindingTypeName(typeDefinition)) { _ in }
     }
 }
 
+/// Writes an extension to an enum to provide the ABIBinding conformance.
+fileprivate func writeEnumBindingExtension(
+        _ enumDefinition: EnumDefinition,
+        projection: Projection,
+        to writer: SwiftSourceFileWriter) throws {
+    let enumBindingProtocol = try projection.isSwiftEnumEligible(enumDefinition)
+        ? SupportModules.WinRT.closedEnumBinding : SupportModules.WinRT.openEnumBinding
+    try writer.writeExtension(
+            attributes: [ Projection.getAvailableAttribute(enumDefinition) ].compactMap { $0 },
+            type: projection.toTypeReference(enumDefinition.bindType()),
+            protocolConformances: [ enumBindingProtocol ]) { writer in
+        // public static var typeName: String { "..." }
+        try writeTypeNameProperty(type: enumDefinition.bindType(), to: writer)
+
+        // public static var ireferenceID: COM.COMInterfaceID { .init(...) }
+        // public static var ireferenceArrayID: COM.COMInterfaceID { .init(...) }
+        try writeIReferenceIDProperties(boxableType: enumDefinition.bindType(), to: writer)
+    }
+}
+
 /// Writes an extension to a struct to provide the ABIBinding conformance.
 fileprivate func writeStructBindingExtension(
         _ structDefinition: StructDefinition,
@@ -99,6 +110,7 @@ fileprivate func writeStructBindingExtension(
 
     // extension <struct>: IReferenceableBinding[, PODBinding]
     try writer.writeExtension(
+            attributes: [ Projection.getAvailableAttribute(structDefinition) ].compactMap { $0 },
             type: .named(projection.toTypeName(structDefinition)),
             protocolConformances: protocolConformances) { writer in
 
@@ -261,7 +273,10 @@ fileprivate func writeClassBindingType(
         ? SupportModules.WinRT.composableClassBinding
         : SupportModules.WinRT.runtimeClassBinding
 
+    // Runtimeclass bindings are classes so they can be found using NSClassFromString,
+    // which allows supporting instantiating the most derived class wrapper when returned from WinRT. 
     try writer.writeClass(
+            attributes: [ Projection.getAvailableAttribute(classDefinition) ].compactMap { $0 },
             visibility: Projection.toVisibility(classDefinition.visibility),
             name: projection.toBindingTypeName(classDefinition),
             protocolConformances: [ bindingProtocol ]) { writer throws in
@@ -362,6 +377,7 @@ fileprivate func writeInterfaceOrDelegateBindingType(
     // Projections of generic instantiations are not owned by any specific module.
     // Making them internal avoids clashes between redundant definitions across modules.
     try writer.writeEnum(
+            attributes: [ Projection.getAvailableAttribute(type.definition) ].compactMap { $0 },
             visibility: type.genericArgs.isEmpty ? Projection.toVisibility(type.definition.visibility) : .internal,
             name: name,
             protocolConformances: [ bindingProtocol ]) { writer throws in

Generator/Sources/SwiftWinRT/Writing/InterfaceDefinition.swift

@@ -136,13 +136,14 @@ fileprivate func writeProtocol(_ interfaceDefinition: InterfaceDefinition, proje
 }
 
 fileprivate func writeProtocolTypeAlias(_ interfaceDefinition: InterfaceDefinition, projection: Projection, to writer: SwiftSourceFileWriter) throws {
-    writer.writeTypeAlias(
+    try writer.writeTypeAlias(
         documentation: projection.getDocumentationComment(interfaceDefinition),
+        attributes: [ Projection.getAvailableAttribute(interfaceDefinition) ].compactMap { $0 },
         visibility: Projection.toVisibility(interfaceDefinition.visibility),
-        name: try projection.toTypeName(interfaceDefinition),
+        name: projection.toTypeName(interfaceDefinition),
         typeParams: interfaceDefinition.genericParams.map { $0.name },
         target: .named(
-            try projection.toProtocolName(interfaceDefinition),
+            projection.toProtocolName(interfaceDefinition),
             genericArgs: interfaceDefinition.genericParams.map {.named($0.name) }).existential())
 }
 
@@ -152,8 +153,10 @@ fileprivate func writeNonthrowingPropertiesExtension(
     let getSetProperties = try interfaceDefinition.properties.filter { try $0.getter != nil }
     guard !getSetProperties.isEmpty else { return }
 
-    let typeName: String = try projection.toProtocolName(interfaceDefinition)
-    try writer.writeExtension(type: .named(typeName)) { writer in
+    let protocolType = SwiftType.named(try projection.toProtocolName(interfaceDefinition))
+    try writer.writeExtension(
+            attributes: [ Projection.getAvailableAttribute(interfaceDefinition) ].compactMap { $0 },
+            type: protocolType) { writer in
         for property in getSetProperties {
             try writeNonthrowingPropertyImplementation(
                 property: property, static: false, projection: projection, to: writer)