[Concurrency] Diagnose initializing actor isolated stored properties with

non-Sendable type from global actor isolated initializers.

(cherry picked from commit 6afd38f)

Author: hborla

lib/Sema/TypeCheckConcurrency.cpp

@@ -5871,12 +5871,16 @@ ActorReferenceResult ActorReferenceResult::forReference(
     return forSameConcurrencyDomain(declIsolation);
   }
 
-  // Initializing a global actor isolated stored property with a value
-  // effectively passes that value from the init context into the global
-  // actor context. This is only okay to do if the property type is Sendable.
-  if (declIsolation.isGlobalActor() && isStoredProperty(declRef.getDecl())) {
+  // Initializing an actor isolated stored property with a value effectively
+  // passes that value from the init context into the actor isolated context.
+  // It's only okay for the value to cross isolation boundaries if the property
+  // type is Sendable. Note that if the init is a nonisolated actor init,
+  // Sendable checking is already performed on arguments at the call-site.
+  if ((declIsolation.isActorIsolated() && contextIsolation.isGlobalActor()) ||
+      declIsolation.isGlobalActor()) {
     auto *init = dyn_cast<ConstructorDecl>(fromDC);
-    if (init && init->isDesignatedInit()) {
+    auto *decl = declRef.getDecl();
+    if (init && init->isDesignatedInit() && isStoredProperty(decl)) {
       auto type =
           fromDC->mapTypeIntoContext(declRef.getDecl()->getInterfaceType());
       if (!isSendableType(fromDC->getParentModule(), type)) {

test/Concurrency/actor_isolation.swift

@@ -824,6 +824,7 @@ actor SomeActorWithInits {
   // expected-note@+1 3 {{mutation of this property is only permitted within the actor}}
   var mutableState: Int = 17
   var otherMutableState: Int
+  // expected-note@+1 {{mutation of this property is only permitted within the actor}}
   let nonSendable: SomeClass
 
   // Sema should not complain about referencing non-sendable members
@@ -887,7 +888,7 @@ actor SomeActorWithInits {
   @MainActor init(i5 x: SomeClass) {
     self.mutableState = 42
     self.otherMutableState = 17
-    self.nonSendable = x
+    self.nonSendable = x // expected-warning {{actor-isolated property 'nonSendable' can not be mutated from the main actor; this is an error in Swift 6}}
 
     self.isolated() // expected-warning{{actor-isolated instance method 'isolated()' can not be referenced from the main actor; this is an error in Swift 6}}
     self.nonisolated()