diff --git a/Boolean_set_operations_2/include/CGAL/Boolean_set_operations_2/Gps_agg_op_surface_sweep_2.h b/Boolean_set_operations_2/include/CGAL/Boolean_set_operations_2/Gps_agg_op_surface_sweep_2.h
index be310948033..33254fee5a0 100644
--- a/Boolean_set_operations_2/include/CGAL/Boolean_set_operations_2/Gps_agg_op_surface_sweep_2.h
+++ b/Boolean_set_operations_2/include/CGAL/Boolean_set_operations_2/Gps_agg_op_surface_sweep_2.h
@@ -193,8 +193,9 @@ public:
 
       // Create the subcurve object.
       using Subcurve_alloc = decltype(this->m_subCurveAlloc);
-      std::allocator_traits<Subcurve_alloc>::construct(this->m_subCurveAlloc, this->m_subCurves + index,
-                                      this->m_masterSubcurve);
+      std::allocator_traits<Subcurve_alloc>::construct(this->m_subCurveAlloc,
+                                                       this->m_subCurves + index,
+                                                       this->m_masterSubcurve);
       (this->m_subCurves + index)->init(*iter);
       (this->m_subCurves + index)->set_left_event(e_left);
       (this->m_subCurves + index)->set_right_event(e_right);