// The shape_refinner_ will be nullptr if shape inference on import is
  // not enabled.
  std::unique_ptr<ShapeRefiner> shape_refiner_ = nullptr;
  NameUniquifier* function_name_uniquifier_;
  mlir::StatusScopedDiagnosticHandler error_handler_;
  // All the TF ops encountered that aren't modelled in dialect.
  llvm::DenseSet<mlir::StringAttr> unmodelled_op_names_;

 protected:
  // Maps feed as TensorId to new Placeholder node name.