syntax_data: {"ast_node_type":"function","tokens":[{"end":92,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn upcast_from(from: ty::Binder<'tcx, PredicateKind<'tcx>>, tcx: TyCtxt<'tcx>) -> Self {
context_before: impl<'tcx> UpcastFrom<TyCtxt<'tcx>, ty::Binder<'tcx, PredicateKind<'tcx>>> for Predicate<'tcx> {
context_after:         tcx.mk_predicate(from)