{"ast_node_type":"variable","tokens":[{"end":69,"kind":"keyword","start":0,"text":"let"}]}
        let block_expr = BlockExpr::cast(arm_body.syntax().clone())?;
    let if_expr: IfExpr = IfExpr::cast(arm_body.syntax().clone()).or_else(|| {
        if let Expr::IfExpr(e) = block_expr.tail_expr()? {