message: [expr] ensure function return value is used
diff: @@ -1534,6 +1534,7 @@ impl<F: FftField> Linearization<Expr<ConstantExpr<F>>> {
  impl<F: One> Expr<F> {
  /// Exponentiate an expression
  + #[must_use]
  pub fn pow(self, p: u64) -> Self {
  use Expr::*;
  if p == 0 {
  