{"ast_node_type":"variable","tokens":[{"end":90,"kind":"keyword","start":0,"text":"if"}]}
                if let Node::TraitItem(ti) = self.infcx.tcx.hir_node_by_def_id(f_in_trait)
                let f_in_trait = f_in_trait.as_local()?;
                    && let hir::TraitItemKind::Fn(sig, _) = ti.kind