syntax_data: {"ast_node_type":"other","tokens":[{"end":61,"kind":"keyword","start":0,"text":"Vec<(ty::PolyTraitPredicate<'tcx>,"}]}
source_snippet:     Vec<(ty::PolyTraitPredicate<'tcx>, SmallVec<[Span; 1]>)>,
context_before: ) -> (
context_after:     Vec<(ty::PolyProjectionPredicate<'tcx>, Span)>,