syntax_data: {"ast_node_type":"variable","tokens":[{"end":84,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                     let bin = ExprKind::Binary { op: BinOp::Add, lhs, rhs: offset };
context_before:                         self.thir.exprs.push(Expr { temp_lifetime, ty: discr_ty, span, kind });
context_after:                     self.thir.exprs.push(Expr { temp_lifetime, ty: discr_ty, span, kind: bin })