syntax_data: {"ast_node_type":"variable","tokens":[{"end":91,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let shifted_alias_ty = fold_regions(self.tcx, unshifted_alias_ty, |re, depth| {
context_before:             // constructing the top-level projection predicate.
context_after:                 if let ty::ReBound(index, bv) = re.kind() {