syntax_data: {"ast_node_type":"other","tokens":[{"end":32,"kind":"keyword","start":0,"text":"traits:"}]}
source_snippet:         traits: &mut FxIndexMap<
context_before:         proj_ty: Option<(DefId, ty::Binder<'tcx, Term<'tcx>>)>,
context_after:             ty::PolyTraitPredicate<'tcx>,