{"ast_node_type":"variable","tokens":[{"end":51,"kind":"keyword","start":0,"text":"let"}]}
        let suffix = Some(ast::UintTy::U32.name());
    pub fn expr_u32(&self, span: Span, n: u32) -> P<ast::Expr> {
        let lit = token::Lit::new(token::Integer, sym::integer(n), suffix);