{"ast_node_type":"other","tokens":[{"end":52,"kind":"keyword","start":0,"text":"(ty::Adt(_,"}]}
            (ty::Adt(_, args), [field], Ok(())) => {
            // `let P() = U;` where `P != U` with `struct P<T>(T);`.
                let field_ty = self.field_ty(pat_span, field, args);