Index: src/Concurrency/Keywords.cc
===================================================================
--- src/Concurrency/Keywords.cc	(revision e04b63656262df0536fe1e7313b9285ad14ac90b)
+++ src/Concurrency/Keywords.cc	(revision cb0e6de65962fd19c1eae698acaec94f1a41b56c)
@@ -331,8 +331,10 @@
 			),
 			new ListInit(
-				map_range < std::list<Initializer*> > ( args, [](DeclarationWithType * var ){
+				map_range < std::list<Initializer*> > ( args, [this](DeclarationWithType * var ){
+					Type * type = var->get_type()->clone();
+					type->set_mutex( false );
 					return new SingleInit( new UntypedExpr(
 						new NameExpr( "get_monitor" ),
-						{  new VariableExpr( var ) }
+						{  new CastExpr( new VariableExpr( var ), type ) }
 					) );
 				})