syntax_data: {"ast_node_type":"other","tokens":[{"end":63,"kind":"keyword","start":0,"text":"proj_ty:"}]}
source_snippet:         proj_ty: Option<(DefId, ty::Binder<'tcx, Term<'tcx>>)>,
context_before:         trait_pred: ty::PolyTraitPredicate<'tcx>,
context_after:         traits: &mut FxIndexMap<