{"ast_node_type":"other","tokens":[{"end":59,"kind":"keyword","start":0,"text":"ty::Dynamic(b_data,"}]}
                    ty::Dynamic(b_data, b_region, ty::Dyn),
                    ty::Dynamic(a_data, a_region, ty::Dyn),
                ) => ecx.consider_builtin_dyn_upcast_candidates(