fix protocols

Author: ktoso

lib/AST/DistributedDecl.cpp

@@ -97,6 +97,10 @@ Type swift::getConcreteReplacementForProtocolActorSystemType(ValueDecl *member)
 }
 
 Type swift::getDistributedActorSystemType(NominalTypeDecl *actor) {
+  assert(!dyn_cast<ProtocolDecl>(actor) &&
+         "Use getConcreteReplacementForProtocolActorSystemType instead to get"
+         "the concrete ActorSystem, if bound, for this DistributedActor "
+         "constrained ProtocolDecl!");
   assert(actor->isDistributedActor());
   auto &C = actor->getASTContext();
 

lib/SIL/IR/SILFunctionBuilder.cpp

@@ -226,11 +226,10 @@ void SILFunctionBuilder::addFunctionAttributes(
     fprintf(stderr, "[%s:%d] (%s) IS DIST THUNK!\n", __FILE__, __LINE__, __FUNCTION__);
     constant.dump();
 
-    // TODO: also handle protocol / extension
-    auto actor = dyn_cast<ClassDecl>(decl->getDeclContext());
+    auto *actor = decl->getDeclContext()->getSelfNominalTypeDecl();
     if (actor && actor->isDistributedActor()) {
       auto &C = decl->getASTContext();
-      auto systemTy = getDistributedActorSystemType(actor);
+      auto systemTy = getConcreteReplacementForProtocolActorSystemType(decl);
       assert(systemTy);
 
       auto decoderTy =