{"ast_node_type":"other","tokens":[{"end":96,"kind":"keyword","start":0,"text":"//"}]}
                    // A<dyn Src<...> + SrcAuto> -> B<dyn Dst<...> + DstAuto>. need to make sure
                match (src_tty.principal(), dst_tty.principal()) {
                    // - `Src` and `Dst` traits are the same