{"ast_node_type":"other","tokens":[{"end":87,"kind":"keyword","start":0,"text":"debug!(\"create_coercion_graph:"}]}
        debug!("create_coercion_graph: pending_obligations={:?}", pending_obligations);
        let pending_obligations = self.fulfillment_cx.borrow_mut().pending_obligations();
        let coercion_edges: Vec<(ty::TyVid, ty::TyVid)> = pending_obligations