{"ast_node_type":"variable","tokens":[{"end":69,"kind":"keyword","start":0,"text":"let"}]}
    let _p = tracing::info_span!("handle_open_cargo_toml").entered();
) -> anyhow::Result<Option<lsp_types::GotoDefinitionResponse>> {
    let file_id = try_default!(from_proto::file_id(&snap, &params.text_document.uri)?);