Please cut a release. Cider 0.16.0 and clj-refactor.el 2.3.1 are incompatible. In clj-refactor.el:
(defun cljr-clean-ns ()
"Clean the ns form for the current buffer.
See: https://github.com/clojure-emacs/clj-refactor.el/wiki/cljr-clean-ns"
(interactive)
(cljr--ensure-op-supported "clean-ns")
(cider-eval-ns-form :sync)
(cljr--clean-ns))
In cider-interaction.el:
(defun cider-eval-ns-form ()
"Evaluate the current buffer's namespace form."
(interactive)
(when (clojure-find-ns)
(save-excursion
(goto-char (match-beginning 0))
(cider-eval-defun-at-point))))
Note that cider-eval-ns-form no longer accepts arguments. In clj-refactor's master branch, cljr-clean-ns no longer passes an argument to cider-eval-ns-form, so I think you just need to make a release of clj-refactor.