{"ast_node_type":"function","tokens":[{"end":94,"kind":"keyword","start":0,"text":"fn"}]}
    fn coerce_from_inference_variable(&self, a: Ty<'tcx>, b: Ty<'tcx>) -> CoerceResult<'tcx> {
    /// fall back to subtyping (`unify_and`).
        debug!("coerce_from_inference_variable(a={:?}, b={:?})", a, b);