syntax_data: {"ast_node_type":"variable","tokens":[{"end":64,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let rhs = recurse_build(tcx, body, rhs, root_span)?;
context_before:             let rhs_ty = body.exprs[rhs].ty;
context_after:             ty::Const::new_expr(tcx, Expr::new_binop(tcx, op, lhs_ty, rhs_ty, lhs, rhs))