{"ast_node_type":"other","tokens":[{"end":89,"kind":"keyword","start":0,"text":"(Some(PointerKind::VTable(src_tty)),"}]}
            (Some(PointerKind::VTable(src_tty)), Some(PointerKind::VTable(dst_tty))) => {
            (Some(PointerKind::Thin), _) => Err(CastError::SizedUnsizedCast),
                let principal = |tty: &Binders<QuantifiedWhereClauses>| {