diff --git a/lib/qcd/action/fermion/WilsonFermion.cc b/lib/qcd/action/fermion/WilsonFermion.cc
index caea055f..053526cd 100644
--- a/lib/qcd/action/fermion/WilsonFermion.cc
+++ b/lib/qcd/action/fermion/WilsonFermion.cc
@@ -82,7 +82,8 @@ namespace QCD {
   template<class Impl>
   void WilsonFermion<Impl>::Mooee(const FermionField &in, FermionField &out) {
     out.checkerboard = in.checkerboard;
-    out = (4.0+mass)*in;
+    typename FermionField::scalar_type scal(4.0+mass);
+    out = scal*in;
   }
   
   template<class Impl>