diff --git a/Eigen/src/Core/functors/UnaryFunctors.h b/Eigen/src/Core/functors/UnaryFunctors.h
index 6ce7ff46b..9b4f49c3c 100644
--- a/Eigen/src/Core/functors/UnaryFunctors.h
+++ b/Eigen/src/Core/functors/UnaryFunctors.h
@@ -533,7 +533,7 @@ struct functor_traits<scalar_cube_op<Scalar> >
   */
 template<typename Scalar> struct scalar_round_op {
   EIGEN_EMPTY_STRUCT_CTOR(scalar_round_op)
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar& a) const { using numext::round; return round(a); }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar& a) const { return numext::round(a); }
   typedef typename packet_traits<Scalar>::type Packet;
   inline Packet packetOp(const Packet& a) const { return internal::pround(a); }
 };
@@ -552,7 +552,7 @@ struct functor_traits<scalar_round_op<Scalar> >
   */
 template<typename Scalar> struct scalar_floor_op {
   EIGEN_EMPTY_STRUCT_CTOR(scalar_floor_op)
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar& a) const { using numext::floor; return floor(a); }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar& a) const { return numext::floor(a); }
   typedef typename packet_traits<Scalar>::type Packet;
   inline Packet packetOp(const Packet& a) const { return internal::pfloor(a); }
 };
@@ -571,7 +571,7 @@ struct functor_traits<scalar_floor_op<Scalar> >
   */
 template<typename Scalar> struct scalar_ceil_op {
   EIGEN_EMPTY_STRUCT_CTOR(scalar_ceil_op)
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar& a) const { using numext::ceil; return ceil(a); }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (const Scalar& a) const { return numext::ceil(a); }
   typedef typename packet_traits<Scalar>::type Packet;
   inline Packet packetOp(const Packet& a) const { return internal::pceil(a); }
 };
@@ -591,7 +591,7 @@ struct functor_traits<scalar_ceil_op<Scalar> >
 template<typename Scalar> struct scalar_isnan_op {
   EIGEN_EMPTY_STRUCT_CTOR(scalar_isnan_op)
   typedef bool result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE result_type operator() (const Scalar& a) const { using numext::isnan; return isnan(a); }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE result_type operator() (const Scalar& a) const { return numext::isnan(a); }
 };
 template<typename Scalar>
 struct functor_traits<scalar_isnan_op<Scalar> >
@@ -609,7 +609,7 @@ struct functor_traits<scalar_isnan_op<Scalar> >
 template<typename Scalar> struct scalar_isinf_op {
   EIGEN_EMPTY_STRUCT_CTOR(scalar_isinf_op)
   typedef bool result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE result_type operator() (const Scalar& a) const { using numext::isinf; return isinf(a); }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE result_type operator() (const Scalar& a) const { return numext::isinf(a); }
 };
 template<typename Scalar>
 struct functor_traits<scalar_isinf_op<Scalar> >
@@ -627,7 +627,7 @@ struct functor_traits<scalar_isinf_op<Scalar> >
 template<typename Scalar> struct scalar_isfinite_op {
   EIGEN_EMPTY_STRUCT_CTOR(scalar_isfinite_op)
   typedef bool result_type;
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE result_type operator() (const Scalar& a) const { using numext::isfinite; return isfinite(a); }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE result_type operator() (const Scalar& a) const { return numext::isfinite(a); }
 };
 template<typename Scalar>
 struct functor_traits<scalar_isfinite_op<Scalar> >