{"ast_node_type":"variable","tokens":[{"end":22,"kind":"keyword","start":0,"text":"let"}]}
    let tcx = fcx.tcx;
fn infer_type_if_missing<'tcx>(fcx: &FnCtxt<'_, 'tcx>, node: Node<'tcx>) -> Option<Ty<'tcx>> {
    let def_id = fcx.body_id;