{"ast_node_type":"other","tokens":[{"end":81,"kind":"keyword","start":0,"text":"Ok(Some(traits::ImplSource::UserDefined(ref"}]}
                    Ok(Some(traits::ImplSource::UserDefined(ref impl_data))) => {
                match self.select_trait_candidate(trait_ref) {
                        // If only a single impl matches, make the error message point