{"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"OpaqueTypes(OpaqueTypeKey<'tcx>,"}]}
    OpaqueTypes(OpaqueTypeKey<'tcx>, Option<OpaqueHiddenType<'tcx>>),
    DuplicateOpaqueType,
    TypeVariables(sv::UndoLog<ut::Delegate<type_variable::TyVidEqKey<'tcx>>>),