diff --git a/src/utils/Messenger.hpp b/src/utils/Messenger.hpp
index bc49cf63f43213260c63a24e2fa48339bb68dd58..2af951e75268a509dbacc15e573e0841f9d05072 100644
--- a/src/utils/Messenger.hpp
+++ b/src/utils/Messenger.hpp
@@ -14,13 +14,10 @@
 #include <mpi.h>
 #endif // PASTIS_HAS_MPI
 
-#warning REMOVE
-enum class CellType : unsigned short;
-
 class Messenger
 {
  private:
-  struct Helper
+  struct helper
   {
 #ifdef PASTIS_HAS_MPI
     template<typename DataType>
@@ -39,7 +36,6 @@ class Messenger
     }
 #endif // PASTIS_HAS_MPI
 
-
    private:
     template <typename T,
               typename Allowed = void>
@@ -107,7 +103,7 @@ class Messenger
 
     const int count = sent_array.size()/m_size;
 
-    MPI_Datatype mpi_datatype = Messenger::Helper::mpiType<SendDataType>();
+    MPI_Datatype mpi_datatype = Messenger::helper::mpiType<SendDataType>();
 
     MPI_Alltoall(&(sent_array[0]), count, mpi_datatype,
                  &(recv_array[0]), count, mpi_datatype,
@@ -132,7 +128,7 @@ class Messenger
 #ifdef PASTIS_HAS_MPI
     std::vector<MPI_Request> request_list;
 
-    MPI_Datatype mpi_datatype = Messenger::Helper::mpiType<SendDataType>();
+    MPI_Datatype mpi_datatype = Messenger::helper::mpiType<SendDataType>();
 
     for (size_t i_send=0; i_send<sent_array_list.size(); ++i_send) {
       const SendArrayType sent_array = sent_array_list[i_send];
@@ -232,7 +228,7 @@ class Messenger
     if constexpr(std::is_arithmetic_v<DataType>) {
       _allToAll(sent_array, recv_array);
     } else if constexpr(std::is_trivial_v<DataType>) {
-      using CastType = Helper::split_cast_t<DataType>;
+      using CastType = helper::split_cast_t<DataType>;
 
       auto send_cast_array = cast_array_to<const CastType>::from(sent_array);
       auto recv_cast_array = cast_array_to<CastType>::from(recv_array);
@@ -282,7 +278,7 @@ class Messenger
     if constexpr(std::is_arithmetic_v<DataType>) {
       _exchange(sent_array_list, recv_array_list);
     } else if constexpr(std::is_trivial_v<DataType>) {
-      using CastType = Helper::split_cast_t<DataType>;
+      using CastType = helper::split_cast_t<DataType>;
       _exchange_through_cast<SendDataType, CastType>(sent_array_list, recv_array_list);
     } else {
       static_assert(std::is_trivial_v<RecvDataType>,
@@ -366,52 +362,52 @@ void exchange(const std::vector<Array<SendDataType>>& sent_array_list,
 #ifdef PASTIS_HAS_MPI
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<char>() {return MPI_CHAR; }
+Messenger::helper::mpiType<char>() {return MPI_CHAR; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<int8_t>() {return MPI_INT8_T; }
+Messenger::helper::mpiType<int8_t>() {return MPI_INT8_T; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<int16_t>() {return MPI_INT16_T; }
+Messenger::helper::mpiType<int16_t>() {return MPI_INT16_T; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<int32_t>() {return MPI_INT32_T; }
+Messenger::helper::mpiType<int32_t>() {return MPI_INT32_T; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<int64_t>() {return MPI_INT64_T; }
+Messenger::helper::mpiType<int64_t>() {return MPI_INT64_T; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<uint8_t>() {return MPI_UINT8_T; }
+Messenger::helper::mpiType<uint8_t>() {return MPI_UINT8_T; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<uint16_t>() {return MPI_UINT16_T; }
+Messenger::helper::mpiType<uint16_t>() {return MPI_UINT16_T; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<uint32_t>() {return MPI_UINT32_T; }
+Messenger::helper::mpiType<uint32_t>() {return MPI_UINT32_T; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<uint64_t>() {return MPI_UINT64_T; }
+Messenger::helper::mpiType<uint64_t>() {return MPI_UINT64_T; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<signed long long int>() {return MPI_LONG_LONG_INT; }
+Messenger::helper::mpiType<signed long long int>() {return MPI_LONG_LONG_INT; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<unsigned long long int>() {return MPI_UNSIGNED_LONG_LONG; }
+Messenger::helper::mpiType<unsigned long long int>() {return MPI_UNSIGNED_LONG_LONG; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<float>() {return MPI_FLOAT; }
+Messenger::helper::mpiType<float>() {return MPI_FLOAT; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<double>() {return MPI_DOUBLE; }
+Messenger::helper::mpiType<double>() {return MPI_DOUBLE; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<long double>() {return MPI_LONG_DOUBLE; }
+Messenger::helper::mpiType<long double>() {return MPI_LONG_DOUBLE; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<wchar_t>() {return MPI_WCHAR; }
+Messenger::helper::mpiType<wchar_t>() {return MPI_WCHAR; }
 
 template<> PASTIS_INLINE MPI_Datatype
-Messenger::Helper::mpiType<bool>() {return MPI_CXX_BOOL; }
+Messenger::helper::mpiType<bool>() {return MPI_CXX_BOOL; }
 
 #endif // PASTIS_HAS_MPI