{"ast_node_type":"other","tokens":[{"end":86,"kind":"keyword","start":0,"text":"hir::TraitFn::Required(params)"}]}
                hir::TraitFn::Required(params) => (sig, generics, None, Some(params)),
            }) => match trait_fn {
                hir::TraitFn::Provided(body) => (sig, generics, Some(body), None),