Merge pull request #71033 from hborla/default-init-isolation

[Concurrency] Handle cases where a property initializer is subsumed by another property for `IsolatedDefaultValues`.

Author: hborla

lib/SILGen/SILGenConstructor.cpp

@@ -1583,9 +1583,20 @@ void SILGenFunction::emitMemberInitializer(DeclContext *dc, VarDecl *selfDecl,
 
     case ActorIsolation::GlobalActor:
     case ActorIsolation::GlobalActorUnsafe:
-    case ActorIsolation::ActorInstance:
-      if (requiredIsolation != contextIsolation)
+    case ActorIsolation::ActorInstance: {
+      if (requiredIsolation != contextIsolation) {
+        // Implicit initializers diagnose actor isolation violations
+        // for property initializers in Sema. Still emit the invalid
+        // member initializer here to avoid duplicate diagnostics and
+        // to preserve warn-until-Swift-6 behavior.
+        auto *init =
+            dyn_cast_or_null<ConstructorDecl>(dc->getAsDecl());
+        if (init && init->isImplicit())
+          break;
+
         continue;
+      }
+    }
     }
 
     auto *varPattern = field->getPattern(i);

lib/Sema/CodeSynthesis.cpp

@@ -350,45 +350,82 @@ static ConstructorDecl *createImplicitConstructor(NominalTypeDecl *decl,
     // initializers apply Sendable checking to arguments at the call-site,
     // and actor initializers do not run on the actor, so initial values
     // cannot be actor-instance-isolated.
-    bool shouldAddNonisolated = true;
-    llvm::Optional<ActorIsolation> existingIsolation = llvm::None;
+    ActorIsolation existingIsolation = getActorIsolation(decl);
     VarDecl *previousVar = nullptr;
+    bool hasError = false;
+
+    // FIXME: Calling `getAllMembers` here causes issues for conformance
+    // synthesis to RawRepresentable and friends. Instead, iterate over
+    // both the stored properties and the init accessor properties, as
+    // those can participate in implicit initializers.
+
+    auto stored = decl->getStoredProperties();
+    auto initAccessor = decl->getInitAccessorProperties();
+
+    auto shouldAddNonisolated = [&](ArrayRef<VarDecl *> properties) {
+      if (hasError)
+        return false;
+
+      bool addNonisolated = true;
+      for (auto *var : properties) {
+        auto *pbd = var->getParentPatternBinding();
+        if (!pbd)
+          continue;
+
+        auto i = pbd->getPatternEntryIndexForVarDecl(var);
+        if (pbd->isInitializerSubsumed(i))
+          continue;
+
+        ActorIsolation initIsolation;
+        if (var->hasInitAccessor()) {
+          // Init accessors share the actor isolation of the property;
+          // the accessor body can call anything in that isolation domain,
+          // and we don't attempt to infer when the isolation isn't
+          // necessary.
+          initIsolation = getActorIsolation(var);
+        } else {
+          initIsolation = var->getInitializerIsolation();
+        }
 
-    // The memberwise init properties are also effectively what the
-    // default init uses, e.g. default initializers initialize via
-    // properties wrapped and init accessors.
-    for (auto var : decl->getMemberwiseInitProperties()) {
-      auto type = var->getTypeInContext();
-      auto isolation = getActorIsolation(var);
-      if (isolation.isGlobalActor()) {
-        if (!type->isSendableType() ||
-            var->getInitializerIsolation().isGlobalActor()) {
-          // If different isolated stored properties require different
-          // global actors, it is impossible to initialize this type.
-          if (existingIsolation &&
-              *existingIsolation != isolation) {
-            ctx.Diags.diagnose(decl->getLoc(),
-                diag::conflicting_stored_property_isolation,
-                ICK == ImplicitConstructorKind::Memberwise,
-                decl->getDeclaredType(), *existingIsolation, isolation);
-            previousVar->diagnose(
-                diag::property_requires_actor,
-                previousVar->getDescriptiveKind(),
-                previousVar->getName(), *existingIsolation);
-            var->diagnose(
-                diag::property_requires_actor,
-                var->getDescriptiveKind(),
-                var->getName(), isolation);
-          }
+        auto type = var->getTypeInContext();
+        auto isolation = getActorIsolation(var);
+        if (isolation.isGlobalActor()) {
+          if (!type->isSendableType() ||
+              initIsolation.isGlobalActor()) {
+            // If different isolated stored properties require different
+            // global actors, it is impossible to initialize this type.
+            if (existingIsolation != isolation) {
+              ctx.Diags.diagnose(decl->getLoc(),
+                  diag::conflicting_stored_property_isolation,
+                  ICK == ImplicitConstructorKind::Memberwise,
+                  decl->getDeclaredType(), existingIsolation, isolation)
+                .warnUntilSwiftVersion(6);
+              if (previousVar) {
+                previousVar->diagnose(
+                    diag::property_requires_actor,
+                    previousVar->getDescriptiveKind(),
+                    previousVar->getName(), existingIsolation);
+              }
+              var->diagnose(
+                  diag::property_requires_actor,
+                  var->getDescriptiveKind(),
+                  var->getName(), isolation);
+              hasError = true;
+              return false;
+            }
 
-          existingIsolation = isolation;
-          previousVar = var;
-          shouldAddNonisolated = false;
+            existingIsolation = isolation;
+            previousVar = var;
+            addNonisolated = false;
+          }
         }
       }
-    }
 
-    if (shouldAddNonisolated) {
+      return addNonisolated;
+    };
+
+    if (shouldAddNonisolated(stored) &&
+        shouldAddNonisolated(initAccessor)) {
       addNonIsolatedToSynthesized(decl, ctor);
     }
   }

test/Concurrency/actor_isolation.swift

@@ -168,9 +168,12 @@ func checkIsolationValueType(_ formance: InferredFromConformance,
 }
 
 // check for instance members that do not need global-actor protection
+
+// expected-warning@+2 {{memberwise initializer for 'NoGlobalActorValueType' cannot be both nonisolated and global actor 'SomeGlobalActor'-isolated; this is an error in Swift 6}}
 // expected-note@+1 2 {{consider making struct 'NoGlobalActorValueType' conform to the 'Sendable' protocol}}
 struct NoGlobalActorValueType {
   @SomeGlobalActor var point: Point // expected-warning {{stored property 'point' within struct cannot have a global actor; this is an error in Swift 6}}
+  // expected-note@-1 {{initializer for property 'point' is global actor 'SomeGlobalActor'-isolated}}
 
   @MainActor let counter: Int // expected-warning {{stored property 'counter' within struct cannot have a global actor; this is an error in Swift 6}}
 

test/Concurrency/global_actor_inference.swift

@@ -559,9 +559,13 @@ struct WrapperOnUnsafeActor<Wrapped> {
   }
 }
 
-// HasWrapperOnUnsafeActor gets an inferred @MainActor attribute.
+// HasWrapperOnUnsafeActor does not have an inferred global actor attribute,
+// because synced and $synced have different global actors.
 struct HasWrapperOnUnsafeActor {
-  @WrapperOnUnsafeActor var synced: Int = 0 // expected-complete-tns-warning {{global actor 'OtherGlobalActor'-isolated default value in a main actor-isolated context; this is an error in Swift 6}}
+// expected-complete-tns-warning@-1 {{memberwise initializer for 'HasWrapperOnUnsafeActor' cannot be both nonisolated and global actor 'OtherGlobalActor'-isolated; this is an error in Swift 6}}
+// expected-complete-tns-warning@-2 {{default initializer for 'HasWrapperOnUnsafeActor' cannot be both nonisolated and global actor 'OtherGlobalActor'-isolated; this is an error in Swift 6}}
+
+  @WrapperOnUnsafeActor var synced: Int = 0 // expected-complete-tns-note 2 {{initializer for property '_synced' is global actor 'OtherGlobalActor'-isolated}}
   // expected-note @-1 3{{property declared here}}
   // expected-complete-tns-note @-2 3{{property declared here}}
 
@@ -586,6 +590,10 @@ struct HasWrapperOnUnsafeActor {
   }
 }
 
+nonisolated func createHasWrapperOnUnsafeActor() {
+  _ = HasWrapperOnUnsafeActor()
+}
+
 // ----------------------------------------------------------------------
 // Nonisolated closures
 // ----------------------------------------------------------------------
@@ -670,7 +678,9 @@ func replacesDynamicOnMainActor() {
 // Global-actor isolation of stored property initializer expressions
 // ----------------------------------------------------------------------
 
+// expected-complete-tns-warning@+1 {{default initializer for 'Cutter' cannot be both nonisolated and main actor-isolated; this is an error in Swift 6}}
 class Cutter {
+  // expected-complete-tns-note@+1 {{initializer for property 'x' is main actor-isolated}}
   @MainActor var x = useFooInADefer()
   @MainActor var y = { () -> Bool in
       var z = statefulThingy

test/Concurrency/isolated_default_arguments.swift

@@ -1,7 +1,5 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend -emit-module -emit-module-path %t/OtherActors.swiftmodule -module-name OtherActors %S/Inputs/OtherActors.swift -disable-availability-checking
-
 // RUN: %target-swift-frontend -I %t  -disable-availability-checking -strict-concurrency=complete -enable-upcoming-feature IsolatedDefaultValues -parse-as-library -emit-sil -o /dev/null -verify %s
 // RUN: %target-swift-frontend -I %t  -disable-availability-checking -strict-concurrency=complete -parse-as-library -emit-sil -o /dev/null -verify -enable-upcoming-feature IsolatedDefaultValues -enable-experimental-feature RegionBasedIsolation %s
 
@@ -151,7 +149,7 @@ struct S2 {
 }
 
 struct S3 {
-  // expected-error@+1 {{default argument cannot be both main actor-isolated and global actor 'SomeGlobalActor'-isolated}}
+  // expected-error@+1 3 {{default argument cannot be both main actor-isolated and global actor 'SomeGlobalActor'-isolated}}
   var (x, y, z) = (requiresMainActor(), requiresSomeGlobalActor(), 10)
 }
 
@@ -196,21 +194,19 @@ extension A {
   }
 }
 
-// expected-error@+1 {{default initializer for 'C1' cannot be both main actor-isolated and global actor 'SomeGlobalActor'-isolated}}
+// expected-warning@+1 {{default initializer for 'C1' cannot be both nonisolated and main actor-isolated; this is an error in Swift 6}}
 class C1 {
   // expected-note@+1 {{initializer for property 'x' is main actor-isolated}}
   @MainActor var x = requiresMainActor()
-  // expected-note@+1 {{initializer for property 'y' is global actor 'SomeGlobalActor'-isolated}}
   @SomeGlobalActor var y = requiresSomeGlobalActor()
 }
 
 class NonSendable {}
 
-// expected-error@+1 {{default initializer for 'C2' cannot be both main actor-isolated and global actor 'SomeGlobalActor'-isolated}}
+// expected-warning@+1 {{default initializer for 'C2' cannot be both nonisolated and main actor-isolated; this is an error in Swift 6}}
 class C2 {
   // expected-note@+1 {{initializer for property 'x' is main actor-isolated}}
   @MainActor var x = NonSendable()
-  // expected-note@+1 {{initializer for property 'y' is global actor 'SomeGlobalActor'-isolated}}
   @SomeGlobalActor var y = NonSendable()
 }
 
@@ -224,8 +220,65 @@ class C3 {
   var y = 0
 }
 
+@MainActor class MultipleVars {
+  var (x, y) = (0, 0)
+}
+
 func callDefaultInit() async {
   _ = C2()
   _ = NonIsolatedInit()
   _ = NonIsolatedInit(x: 10)
+  _ = MultipleVars()
+}
+
+// expected-warning@+1 {{default initializer for 'MultipleVarsInvalid' cannot be both nonisolated and main actor-isolated; this is an error in Swift 6}}
+class MultipleVarsInvalid {
+  // expected-note@+1 {{initializer for property 'x' is main actor-isolated}}
+  @MainActor var (x, y) = (requiresMainActor(), requiresMainActor())
+}
+
+@propertyWrapper 
+@preconcurrency @MainActor
+struct RequiresMain<Value>  {
+  var wrappedValue: Value
+
+  init(wrappedValue: Value) {
+    self.wrappedValue = wrappedValue
+  }
+}
+
+// This is okay; UseRequiresMain has an inferred 'MainActor'
+// attribute.
+struct UseRequiresMain {
+  @RequiresMain private var x = 10
+}
+
+nonisolated func test() async {
+  // expected-warning@+2 {{expression is 'async' but is not marked with 'await'; this is an error in Swift 6}}
+  // expected-note@+1 {{calls to initializer 'init()' from outside of its actor context are implicitly asynchronous}}
+  _ = UseRequiresMain()
+}
+
+// expected-warning@+2 {{memberwise initializer for 'InitAccessors' cannot be both nonisolated and main actor-isolated; this is an error in Swift 6}}
+// expected-warning@+1 {{default initializer for 'InitAccessors' cannot be both nonisolated and main actor-isolated; this is an error in Swift 6}}
+struct InitAccessors {
+  private var _a: Int
+
+  // expected-note@+1 2 {{initializer for property 'a' is main actor-isolated}}
+  @MainActor var a: Int = 5 {
+    @storageRestrictions(initializes: _a)
+    init {
+      _a = requiresMainActor()
+    }
+    get {
+      _a
+    }
+  }
+}
+
+// Make sure isolation inference for implicit initializers
+// doesn't impact conformance synthesis.
+
+struct CError: Error, RawRepresentable {
+  var rawValue: CInt
 }