syntax_data: {"ast_node_type":"variable","tokens":[{"end":55,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let fields = iter::zip(*elem_tys, branches)
context_before:         ty::Tuple(elem_tys) => {
context_after:                 .map(|(elem_ty, elem_valtree)| ty::Const::new_value(tcx, *elem_valtree, elem_ty))