Remove useless statements

src/mesh/ItemValue.hpp

@@ -95,13 +95,10 @@ class ItemValue
   }
 
   template <typename IndexType>
-  DataType& operator[](const IndexType& i) const noexcept(NO_ASSERT)
+  DataType& operator[](const IndexType&) const noexcept(NO_ASSERT)
   {
     static_assert(std::is_same_v<IndexType,ItemId>,
                   "ItemValue must be indexed by ItemId");
-    static_assert(not std::is_const_v<DataType>,
-                  "Cannot modify ItemValue of const");
-    return m_values[i];
   }
 
   PASTIS_INLINE