message: fix clang error
diff: @@ -109,8 +109,11 @@ protected:
  */
  explicit Reflection(std::shared_ptr<const LinOp> coef,
  std::shared_ptr<const LinOp> U)
  - : Reflection(std::move(coef), std::move(U),
  - std::move(as<Transposable>(lend(U))->conj_transpose()))
  + : Reflection(
  + std::move(coef),
  + // U can not be std::move(U). it will delete U before the
  + // transpose operation
  + U, std::move((as<gko::Transposable>(lend(U)))->conj_transpose()))
  {}
  /**
  