Merge pull request swiftlang#36476 from DougGregor/global-actor-mangling-hack

Author: swift-ci

lib/AST/ASTMangler.cpp

@@ -2857,10 +2857,21 @@ CanType ASTMangler::getDeclTypeForMangling(
     return C.TheErrorType;
   }
 
+  Type ty = decl->getInterfaceType()->getReferenceStorageReferent();
+
+  // Strip the global actor out of the mangling.
+  ty = ty.transform([](Type type) {
+    if (auto fnType = type->getAs<AnyFunctionType>()) {
+      if (fnType->getGlobalActor()) {
+        return Type(fnType->withExtInfo(
+            fnType->getExtInfo().withGlobalActor(Type())));
+      }
+    }
+
+    return type;
+  });
 
-  auto canTy = decl->getInterfaceType()
-                   ->getReferenceStorageReferent()
-                   ->getCanonicalType();
+  auto canTy = ty->getCanonicalType();
 
   if (auto gft = dyn_cast<GenericFunctionType>(canTy)) {
     genericSig = gft.getGenericSignature();

test/SILGen/global_actor_function_mangling.swift

@@ -0,0 +1,9 @@
+// RUN: %target-swift-frontend -emit-silgen %s -module-name test -swift-version 5 -enable-experimental-concurrency | %FileCheck %s
+// REQUIRES: concurrency
+
+// Declarations don't mangle global actor types.
+// CHECK: @$s4test10returnsOptyxycSgAClF
+func returnsOpt<R>(_ fn: (@MainActor () -> R)?) -> (() -> R)? {
+  typealias Fn = (() -> R)?
+  return unsafeBitCast(fn, to: Fn.self)
+}