Walk auxiliary declarations when gathering stored properties

lib/Sema/TypeCheckStorage.cpp

@@ -169,14 +169,23 @@ static void computeLoweredStoredProperties(NominalTypeDecl *decl,
 static void enumerateStoredPropertiesAndMissing(
     NominalTypeDecl *decl,
     IterableDeclContext *implDecl,
-    llvm::function_ref<void(VarDecl *)> addStoredProperty,
+    llvm::function_ref<void(VarDecl *)> _addStoredProperty,
     llvm::function_ref<void(MissingMemberDecl *)> addMissing) {
+  // Add a variable as a stored properties.
+  llvm::SmallSet<VarDecl *, 8> knownStoredProperties;
+  auto addStoredProperty = [&](VarDecl *var) {
+    if (!var->isStatic() && var->hasStorage()) {
+      if (knownStoredProperties.insert(var).second)
+        _addStoredProperty(var);
+    }
+  };
+
   // If we have a distributed actor, find the id and actorSystem
   // properties. We always want them first, and in a specific
   // order.
-  VarDecl *distributedActorId = nullptr;
-  VarDecl *distributedActorSystem = nullptr;
   if (decl->isDistributedActor()) {
+    VarDecl *distributedActorId = nullptr;
+    VarDecl *distributedActorSystem = nullptr;
     ASTContext &ctx = decl->getASTContext();
     for (auto *member : implDecl->getMembers()) {
       if (auto *var = dyn_cast<VarDecl>(member)) {
@@ -201,17 +210,14 @@ static void enumerateStoredPropertiesAndMissing(
 
   for (auto *member : implDecl->getMembers()) {
     if (auto *var = dyn_cast<VarDecl>(member)) {
-      if (!var->isStatic() && var->hasStorage()) {
-        // Skip any properties that we already emitted explicitly
-        if (var == distributedActorId)
-          continue;
-        if (var == distributedActorSystem)
-          continue;
-
-        addStoredProperty(var);
-      }
+      addStoredProperty(var);
     }
 
+    member->visitAuxiliaryDecls([&](Decl *auxDecl) {
+      if (auto auxVar = dyn_cast<VarDecl>(auxDecl))
+        addStoredProperty(auxVar);
+    });
+
     if (auto missing = dyn_cast<MissingMemberDecl>(member))
       if (missing->getNumberOfFieldOffsetVectorEntries() > 0)
         addMissing(missing);

test/Macros/Inputs/syntax_macro_definitions.swift

@@ -406,6 +406,29 @@ extension PropertyWrapperMacro: AccessorMacro, Macro {
   }
 }
 
+extension PropertyWrapperMacro: PeerMacro {
+  public static func expansion(
+    of node: AttributeSyntax,
+    providingPeersOf declaration: some DeclSyntaxProtocol,
+    in context: some MacroExpansionContext
+  ) throws -> [DeclSyntax] {
+    guard let varDecl = declaration.as(VariableDeclSyntax.self),
+      let binding = varDecl.bindings.first,
+      let identifier = binding.pattern.as(IdentifierPatternSyntax.self)?.identifier,
+      binding.accessor == nil,
+      let type = binding.typeAnnotation?.type
+    else {
+      return []
+    }
+
+    return [
+      """
+      var _\(raw: identifier.trimmedDescription): MyWrapperThingy<\(type)>
+      """
+    ]
+  }
+}
+
 public struct WrapAllProperties: MemberAttributeMacro {
   public static func expansion(
     of node: AttributeSyntax,

test/Macros/macro_expand_peers.swift

@@ -128,6 +128,9 @@ struct Main {
     }
     print(result2)
     // CHECK-EXEC: hahaha global
+
+    // CHECK-EXEC: MyWrapperThingy<Swift.Int>(storage: 5)
+    print(S3(x: 5))
   }
 }
 
@@ -156,3 +159,36 @@ struct S2 {
   }
   #endif
 }
+
+// Stored properties generated by a peer macro
+@attached(accessor)
+@attached(peer, names: prefixed(_))
+macro myPropertyWrapper() =
+    #externalMacro(module: "MacroDefinition", type: "PropertyWrapperMacro")
+
+struct Date { }
+
+struct MyWrapperThingy<T> {
+  var storage: T
+
+  var wrappedValue: T {
+    get {
+      print("Getting value \(storage)")
+      return storage
+    }
+
+    set {
+      print("Setting value \(newValue)")
+      storage = newValue
+    }
+  }
+}
+
+struct S3 {
+  @myPropertyWrapper
+  var x: Int = 0
+
+  init(x: Int) {
+    self._x = MyWrapperThingy(storage: x)
+  }
+}