fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
self.super_constant(constant, location);
let Constant { span, user_ty, literal } = constant;
fn visit_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
self.super_constant(constant, location);
let Constant { span, user_ty, literal } = constant;