Andrew Christianson wrote:
> -	     (make-directory newname t)))
> +	     (make-directory newname t))
> +            ((and copy-contents (not (file-directory-p newname)))
> +             (make-directory newname parents)))

Thanks for clarifying the test case and for the proposed patch. I reproduced the 
bug on Fedora 26 and wrote a test case to test case for the bug. Although the 
abovementioned patch should work on Fedora, it won't work on platforms that do 
not allow trailing / on mkdir arguments. So I installed the attached patch into 
the emacs-26 branch, and am boldly marking this bug as fixed. Please give it a try.