syntax_data: {"ast_node_type":"other","tokens":[{"end":62,"kind":"keyword","start":0,"text":"unnormalized_upcast_principal:"}]}
source_snippet:         unnormalized_upcast_principal: ty::PolyTraitRef<'tcx>,
context_before:         obligation: &PolyTraitObligation<'tcx>,
context_after:         a_data: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,