{"ast_node_type":"function","tokens":[{"end":75,"kind":"keyword","start":0,"text":"fn"}]}
    fn show_definition(&self, err: &mut Diag<'_, impl EmissionGuarantee>) {
    /// Builds the `type defined here` message.
        let mut spans: MultiSpan = if let Some(def_span) = self.tcx.def_ident_span(self.def_id) {