{"ast_node_type":"variable","tokens":[{"end":65,"kind":"keyword","start":0,"text":"let"}]}
                    let content_ty = fx.monomorphize(content_ty);
                Rvalue::ShallowInitBox(ref operand, content_ty) => {
                    let box_layout = fx.layout_of(Ty::new_box(fx.tcx, content_ty));