Merge pull request swiftlang#22691 from aschwaighofer/allow_dynamic_replacement_init_non_delegating

Allow dynamic replacement initializers to be non delegating

Author: aschwaighofer

lib/AST/Decl.cpp

@@ -6344,8 +6344,10 @@ ConstructorDecl::getDelegatingOrChainedInitKind(DiagnosticEngine *diags,
       // Prior to Swift 5, cross-module initializers were permitted to be
       // non-delegating. However, if the struct isn't fixed-layout, we have to
       // be delegating because, well, we don't know the layout.
+      // A dynamic replacement is permitted to be non-delegating.
       if (NTD->isResilient() ||
-          containingModule->getASTContext().isSwiftVersionAtLeast(5)) {
+          (containingModule->getASTContext().isSwiftVersionAtLeast(5) &&
+           !getAttrs().getAttribute<DynamicReplacementAttr>())) {
         if (containingModule != NTD->getParentModule())
           Kind = BodyInitKind::Delegating;
       }

lib/Sema/TypeCheckDecl.cpp

@@ -4047,7 +4047,8 @@ void TypeChecker::validateDecl(ValueDecl *D) {
       // (or the same file) to add vtable entries, we can re-evaluate this
       // restriction.
       if (extType->getClassOrBoundGenericClass() &&
-          isa<ExtensionDecl>(CD->getDeclContext())) {
+          isa<ExtensionDecl>(CD->getDeclContext()) &&
+          !(CD->getAttrs().hasAttribute<DynamicReplacementAttr>())) {
         diagnose(CD->getLoc(), diag::designated_init_in_extension, extType)
           .fixItInsert(CD->getLoc(), "convenience ");
         CD->setInitKind(CtorInitializerKind::Convenience);

test/Sema/Inputs/dynamic_replacements_init_A.swift

@@ -0,0 +1,32 @@
+struct S {
+    let i: Int
+    init(i: Int) {
+        self.i = i
+    }
+
+    init(y: Int) {
+      self.init(i: y)
+    }
+}
+
+class A {
+  let i: Int
+  init(i: Int) {
+    self.i = i
+  }
+  convenience init(c: Int) {
+    self.init(i: c)
+  }
+}
+
+class B : A {
+  let b: Int
+  init(b: Int, i: Int) {
+    self.b = b
+    super.init(i: i)
+  }
+
+  convenience init(x: Int) {
+    self.init(b: x, i: x)
+  }
+}

test/Sema/dynamic_replacement_init.swift

@@ -0,0 +1,41 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -swift-version 5 -enable-implicit-dynamic -enable-private-imports -emit-module -primary-file %S/Inputs/dynamic_replacements_init_A.swift -emit-module -module-name ModuleA -emit-module-path %t/ModuleA.swiftmodule
+// RUN: %target-swift-frontend -swift-version 5 -typecheck -verify %s -I %t
+
+@_private(sourceFile: "dynamic_replacements_init_A.swift") import ModuleA
+
+extension S {
+  @_dynamicReplacement(for: init(i:))
+  private init(_i: Int) {
+    self.i = _i
+  }
+  @_dynamicReplacement(for: init(y:))
+  private init(_y: Int) {
+    self.init(i: _y)
+  }
+}
+
+extension A {
+  @_dynamicReplacement(for: init(i:))
+  private init(_i: Int) {
+    self.i = _i
+  }
+
+  @_dynamicReplacement(for: init(c:))
+  private convenience init(_y: Int) {
+    self.init(i: _y)
+  }
+}
+
+extension B {
+  @_dynamicReplacement(for: init(b:i:))
+  private init(_i: Int, _b: Int) {
+    self.b = _b
+    super.init(i: _i)
+  }
+
+  @_dynamicReplacement(for: init(x:))
+  private convenience init(_i: Int) {
+    self.init(b: _i, i: _i)
+  }
+}