diff --git a/BGL/include/CGAL/boost/graph/IO/3MF.h b/BGL/include/CGAL/boost/graph/IO/3MF.h
index 33e6c6a823f..6246950a0d1 100644
--- a/BGL/include/CGAL/boost/graph/IO/3MF.h
+++ b/BGL/include/CGAL/boost/graph/IO/3MF.h
@@ -59,9 +59,9 @@ bool write_3MF(const std::string& filename,
                const GraphRange& gs,
                const std::vector<std::string>& names
 #ifndef DOXYGEN_RUNNING
-               , std::enable_if_t<!
-                   internal::is_Point_set_or_Range_or_Iterator<
-                     typename boost::range_value<GraphRange>::type>::value>* = nullptr
+               , std::enable_if_t<
+                   ! internal::is_Point_set_or_Range_or_Iterator<
+                       typename boost::range_value<GraphRange>::type>::value>* = nullptr
 #endif
                )
 {
diff --git a/HalfedgeDS/include/CGAL/HalfedgeDS_const_decorator.h b/HalfedgeDS/include/CGAL/HalfedgeDS_const_decorator.h
index 14093079bce..6e3428f9861 100644
--- a/HalfedgeDS/include/CGAL/HalfedgeDS_const_decorator.h
+++ b/HalfedgeDS/include/CGAL/HalfedgeDS_const_decorator.h
@@ -133,8 +133,8 @@ normalized_border_is_valid( bool verb) const {
 
     Halfedge_const_iterator e = hds->halfedges_begin();
     size_type count = 0;
-    while( e != hds->halfedges_end() && ! e->is_border() && !
-           e->opposite()->is_border()) {
+    while( e != hds->halfedges_end() && ! e->is_border() &&
+           ! e->opposite()->is_border()) {
         ++e;
         ++e;
         ++count;
diff --git a/Nef_S2/include/CGAL/Nef_S2/SM_io_parser.h b/Nef_S2/include/CGAL/Nef_S2/SM_io_parser.h
index 994c6a41b80..06909c029b9 100644
--- a/Nef_S2/include/CGAL/Nef_S2/SM_io_parser.h
+++ b/Nef_S2/include/CGAL/Nef_S2/SM_io_parser.h
@@ -241,9 +241,8 @@ bool SM_io_parser<Decorator_>::read_edge(SHalfedge_handle e)
        !(in >> m) || !check_sep(",") ||
        !(in >> k) || !check_sep("}") )
     return false;
-  if (!
-     (eo >= 0 && eo < en && epr >= 0 && epr < en && ene >= 0 && ene < en &&
-      v >= 0 && v < vn && f >= 0 && f < fn ))
+  if (! (eo >= 0 && eo < en && epr >= 0 && epr < en && ene >= 0 && ene < en &&
+         v >= 0 && v < vn && f >= 0 && f < fn ))
   {
     std::cerr<<"wrong index in read_edge"<<std::endl;
     in.setstate(std::ios_base::badbit);