syntax_data: {"ast_node_type":"variable","tokens":[{"end":62,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let (size, signed) = self.ty.int_size_and_signed(tcx);
context_before:     pub fn checked_add(self, tcx: TyCtxt<'tcx>, n: u128) -> (Self, bool) {
context_after:         let (val, oflo) = if signed {