message: fix a bug (thanks clang)
diff: @@ -589,7 +589,7 @@ namespace RINGMesh
  index_t RelationshipManager::find_boundary_relationship(
  const gmme_id& incident_entity, const gmme_id& boundary )
  {
  - return find_boundary_relationship( incident_entity, boundary );
  + return impl_->find_boundary_relationship( incident_entity, boundary );
  }
  index_t RelationshipManager::find_parent_child_relationship(
  