Merge pull request swiftlang#75605 from gottesmm/pr-d4066f062c015e630d51fe05140fe756391079a9

[region-isolation] Use a hard to use API correctly.

Author: gottesmm

lib/SILOptimizer/Mandatory/TransferNonSendable.cpp

@@ -1982,7 +1982,8 @@ void AssignIsolatedIntoSendingResultDiagnosticEmitter::emit() {
     // string a path component for that class_method.
     if (info.srcOperand->get()->getType() != info.outSendingResult->getType()) {
       if (auto fas = FullApplySite::isa(info.srcOperand->getUser())) {
-        if (fas.getSelfArgument() == info.srcOperand->get() &&
+        if (fas.hasSelfArgument() &&
+            fas.getSelfArgument() == info.srcOperand->get() &&
             fas.getNumIndirectSILResults() == 1) {
           // First check if our function argument is exactly our out parameter.
           bool canEmit =

test/Concurrency/transfernonsendable.swift

@@ -1849,3 +1849,18 @@ func testBooleanCapture(_ x: inout NonSendableKlass) {
     print(z)
   }
 }
+
+public class Context {
+  let value: Int
+
+  init(value: Int) {
+    self.value = value
+  }
+}
+
+extension MyActor {
+  public func withContext<T>(_ block: sending (NonSendableKlass) throws -> T) async throws -> sending T {
+    return try block(klass) // expected-tns-warning {{returning 'self'-isolated 'self.klass' as a 'sending' result risks causing data races}}
+    // expected-tns-note @-1 {{returning 'self'-isolated 'self.klass' risks causing data races since the caller assumes that 'self.klass' can be safely sent to other isolation domains}}
+  }
+}