{"ast_node_type":"variable","tokens":[{"end":62,"kind":"keyword","start":0,"text":"let"}]}
    let fn_ctxt = FnCtxt::new(&root_ctxt, param_env, body_id);
    let root_ctxt = crate::typeck_root_ctxt::TypeckRootCtxt::new(tcx, body_id);
    fn_ctxt.may_coerce(ty, output_ty)