syntax_data: {"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":")"}]}
source_snippet:     ) -> Result<ty::Const<'tcx>, Vec<E>> {
context_before:         fulfill_cx: &mut dyn TraitEngine<'tcx, E>,
context_after:         if self.infcx.tcx.features().generic_const_exprs() {