{"ast_node_type":"other","tokens":[{"end":54,"kind":"keyword","start":0,"text":")"}]}
    ) -> (&'hir [hir::Param<'hir>], hir::Expr<'hir>) {
        coroutine_source: hir::CoroutineSource,
        let mut parameters: Vec<hir::Param<'_>> = Vec::new();