{"ast_node_type":"variable","tokens":[{"end":43,"kind":"keyword","start":0,"text":"let"}]}
        let m_i1s = bx.bitcast(m_im, i1xn);
        let m_im = bx.trunc(mask, im);
        return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));