{"ast_node_type":"other","tokens":[{"end":77,"kind":"keyword","start":0,"text":"(PointerKind::VTable(src_tty),"}]}
            (PointerKind::VTable(src_tty), PointerKind::VTable(dst_tty)) => {
            // trait object -> trait object? need to do additional checks
                match (src_tty.principal(), dst_tty.principal()) {