{"ast_node_type":"variable","tokens":[{"end":87,"kind":"keyword","start":0,"text":"let"}]}
    let wf_obligations = bounds.iter_identity_copied().flat_map(|(bound, bound_span)| {
    debug!("check_associated_type_bounds: bounds={:?}", bounds);
        let normalized_bound = wfcx.normalize(span, None, bound);