syntax_data: {"ast_node_type":"other","tokens":[{"end":51,"kind":"keyword","start":0,"text":"Vec<(ty::PolyProjectionPredicate<'tcx>,"}]}
source_snippet:     Vec<(ty::PolyProjectionPredicate<'tcx>, Span)>,
context_before:     Vec<(ty::PolyTraitPredicate<'tcx>, SmallVec<[Span; 1]>)>,
context_after: ) {