[Concurrency] Handle #isolation in isolated argument checking.

Author: hborla

lib/AST/Decl.cpp

@@ -11238,9 +11238,6 @@ ActorIsolation::forActorInstanceParameter(Expr *actor,
                                           unsigned parameterIndex) {
   auto &ctx = actor->getType()->getASTContext();
 
-  if (auto *isolation = dyn_cast<CurrentContextIsolationExpr>(actor))
-    actor = isolation->getActor();
-
   // An isolated value of `nil` is statically nonisolated.
   // FIXME: Also allow 'Optional.none'
   if (dyn_cast<NilLiteralExpr>(actor))

lib/Sema/TypeCheckConcurrency.cpp

@@ -3281,6 +3281,17 @@ namespace {
           continue;
 
         auto *arg = args->getExpr(paramIdx);
+
+        // FIXME: CurrentContextIsolationExpr does not have its actor set
+        // at this point.
+        if (auto *macro = dyn_cast<MacroExpansionExpr>(arg)) {
+          auto *expansion = macro->getRewritten();
+          if (auto *isolation = dyn_cast<CurrentContextIsolationExpr>(expansion)) {
+            recordCurrentContextIsolation(isolation);
+            arg = isolation->getActor();
+          }
+        }
+
         argForIsolatedParam = arg;
         if (getIsolatedActor(arg))
           continue;

test/Concurrency/isolated_parameters.swift

@@ -442,18 +442,22 @@ func sync(isolatedTo actor: isolated (any Actor)?) {}
 func preciseIsolated(a: isolated MyActor) async {
   sync(isolatedTo: a)
   sync(isolatedTo: nil) // okay from anywhere
+  sync(isolatedTo: #isolation)
 
   Task { @MainActor in
     sync(isolatedTo: MainActor.shared)
     sync(isolatedTo: nil) // okay from anywhere
+    sync(isolatedTo: #isolation)
   }
 
   Task { @MyGlobal in
     sync(isolatedTo: MyGlobal.shared)
     sync(isolatedTo: nil) // okay from anywhere
+    sync(isolatedTo: #isolation)
   }
 
   Task.detached {
     sync(isolatedTo: nil) // okay from anywhere
+    sync(isolatedTo: #isolation)
   }
 }