diff --git a/buildconfig/class_maker.py b/buildconfig/class_maker.py
index b0d6d8f541a29f136cfe188e9777eab6ad6ea1de..fe4aa261fc359d9cbbe15d7c99400eb953c55700 100755
--- a/buildconfig/class_maker.py
+++ b/buildconfig/class_maker.py
@@ -134,10 +134,12 @@ const std::string %s::summary() const {
  */
 void %s::init() {
   declareProperty(
-      new WorkspaceProperty<>("InputWorkspace", "", Direction::Input),
+      Kernel::make_unique<WorkspaceProperty<API::Workspace>>("InputWorkspace", "",
+                                                             Direction::Input),
       "An input workspace.");
   declareProperty(
-      new WorkspaceProperty<>("OutputWorkspace", "", Direction::Output),
+      Kernel::make_unique<WorkspaceProperty<API::Workspace>>("OutputWorkspace", "",
+                                                             Direction::Output),
       "An output workspace.");
 }