{"ast_node_type":"other","tokens":[{"end":61,"kind":"keyword","start":0,"text":"//"}]}
        // Otherwise, co + co = co, contra + contra = contra.
        (ty::Contravariant, ty::Covariant) | (ty::Covariant, ty::Contravariant) => ty::Invariant,
        (ty::Contravariant, ty::Contravariant) => ty::Contravariant,