Merge pull request #72565 from hborla/6.0-dispatch-main-actor

[6.0][Concurrency] Apply `@MainActor` to main dispatch queue operations without considering `Sendable`.

Author: hborla

lib/Sema/TypeCheckConcurrency.cpp

@@ -6058,6 +6058,7 @@ swift::isDispatchQueueOperationName(StringRef name) {
       .Case("sync", DispatchQueueOperation::Normal)
       .Case("async", DispatchQueueOperation::Sendable)
       .Case("asyncAndWait", DispatchQueueOperation::Normal)
+      .Case("asyncUnsafe", DispatchQueueOperation::Normal)
       .Case("asyncAfter", DispatchQueueOperation::Sendable)
       .Case("concurrentPerform", DispatchQueueOperation::Sendable)
       .Default(std::nullopt);
@@ -6155,8 +6156,7 @@ static AnyFunctionType *applyUnsafeConcurrencyToFunctionType(
     // @MainActor occurs in concurrency contexts or those where we have an
     // application.
     bool addSendable = knownUnsafeParams && inConcurrencyContext;
-    bool addMainActor =
-        (isMainDispatchQueue && knownUnsafeParams) &&
+    bool addMainActor = isMainDispatchQueue &&
         (inConcurrencyContext || numApplies >= 1);
     Type newParamType = param.getPlainType();
     if (addSendable || addMainActor) {

test/Concurrency/dispatch_inference.swift

@@ -17,6 +17,10 @@ func testMe() {
   DispatchQueue.main.async {
     onlyOnMainActor() // okay, due to inference of @MainActor-ness
   }
+
+  DispatchQueue.main.sync {
+    onlyOnMainActor()
+  }
 }
 
 func testUnsafeSendableInMainAsync() async {