diff --git a/src/lib/diff/tree-mutator-gen-node-binding.hpp b/src/lib/diff/tree-mutator-gen-node-binding.hpp
index 95f063edf..275b73bbf 100644
--- a/src/lib/diff/tree-mutator-gen-node-binding.hpp
+++ b/src/lib/diff/tree-mutator-gen-node-binding.hpp
@@ -128,7 +128,8 @@ namespace diff{
     inline Builder<ObjectTypeHandler<MUT>>
     filterObjectTypeAttribute (Rec::Mutator& targetTree, Builder<MUT>&& chain)
     {
-      return ObjectTypeHandler<MUT> {targetTree, move(chain)};
+      using ObTyHa = ObjectTypeHandler<MUT>;
+      return Builder<ObTyHa>{ObTyHa {targetTree, move(chain)}};
     }
     
     
diff --git a/src/lib/diff/tree-mutator.hpp b/src/lib/diff/tree-mutator.hpp
index c09c04cc5..7d50a5cd0 100644
--- a/src/lib/diff/tree-mutator.hpp
+++ b/src/lib/diff/tree-mutator.hpp
@@ -316,6 +316,7 @@ namespace diff{
     struct Builder
       : PAR
       {
+        explicit
         Builder(PAR&& par)
           : PAR{forward<PAR> (par)}
           { }
@@ -469,7 +470,7 @@ namespace diff{
   inline Builder<TreeMutator>
   TreeMutator::build ()
   {
-    return TreeMutator();
+    return Builder<TreeMutator>{TreeMutator()};
   }