diff --git a/Alpha_shapes_2/include/CGAL/Alpha_shapes_2/internal/Lazy_alpha_nt_2.h b/Alpha_shapes_2/include/CGAL/Alpha_shapes_2/internal/Lazy_alpha_nt_2.h
index c2fa9ca8d71..fb2b69ce073 100644
--- a/Alpha_shapes_2/include/CGAL/Alpha_shapes_2/internal/Lazy_alpha_nt_2.h
+++ b/Alpha_shapes_2/include/CGAL/Alpha_shapes_2/internal/Lazy_alpha_nt_2.h
@@ -229,7 +229,7 @@ public:
         approx_ = Approx_squared_radius()( to_approx(*data().p0),to_approx(*data().p1),to_approx(*data().p2) );
         break;
       default:
-        CGAL_unreachable());
+        CGAL_unreachable();
     }
   }
 
diff --git a/Cone_spanners_2/include/CGAL/Construct_theta_graph_2.h b/Cone_spanners_2/include/CGAL/Construct_theta_graph_2.h
index d4b47ed33c2..d36a7068f14 100644
--- a/Cone_spanners_2/include/CGAL/Construct_theta_graph_2.h
+++ b/Cone_spanners_2/include/CGAL/Construct_theta_graph_2.h
@@ -99,10 +99,7 @@ public:
                             ): cone_number(k), cones_choice(cones_selected), rays(std::vector<Direction_2>(k))
 
     {
-        if (k<2) {
-            std::cout << "The number of cones must be larger than 1!" << std::endl;
-            CGAL_assertion(false);
-        }
+        CGAL_assertion_msg(k>1, "The number of cones must be larger than 1");
 
         /* Initialize a functor, specialization will happen here depending on the kernel type to
          compute the cone boundaries either exactly or inexactly */
diff --git a/Kinetic_space_partition/include/CGAL/KSP_3/Finalizer.h b/Kinetic_space_partition/include/CGAL/KSP_3/Finalizer.h
index 8b1c033e8b4..6b225fa4f57 100644
--- a/Kinetic_space_partition/include/CGAL/KSP_3/Finalizer.h
+++ b/Kinetic_space_partition/include/CGAL/KSP_3/Finalizer.h
@@ -414,7 +414,7 @@ private:
       return true;
     }
 
-    CGAL_assertion(false);
+    CGAL_unreachable();
     return false;
   }
 
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h
index 4d5622c6f0d..b2188894a67 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h
@@ -1940,7 +1940,7 @@ private:
         else if(is_on_mesh(h))          nb_mesh++;
         else if(is_on_border(h))        nb_border++;
         else if(is_an_isolated_constraint(h)) nb_isolated++;
-        else CGAL_assertion(false);
+        else CGAL_unreachable();
       }
       CGAL_USE(nb_border);
       CGAL_USE(nb_mesh);