I see. Seems current ob-core.el can filter out the `src-coderef`.
Like the following:

#+begin_src emacs-lisp
(prin1 "hello, world!") (ref:hello)
#+end_src

#+RESULTS[<2018-01-25 20:28:40> 16eccfedcc87d3ca0c7024b2637c646d4708ec42]:
: hello, world!

#+begin_src ruby :results output
puts "hello, world!" (ref:hello)
#+end_src

#+RESULTS[<2018-01-25 20:46:21> e1e8632ccedf7cc3c676be0c89841a885bbcc7d9]:
: hello, world!

But about your questions:
> What it the comment syntax is not properly defined?
I think almost all programming language has comments. About some other
babels which don't have comment. I think `org-babel` can check whether
babel language has comment.
> What if the coderef format already contains comment syntax?
`org-babel` already use current coderef format. Keep current coderef format
is fine. If coderef format is like `#ref:label`. and Ruby language use
comment `#` too. Then after prepending comment char, it becomes `#
#ref:label`. It is fine. Right?
> What if the language does not support inline comments and you're in the
middle of a line?
It is fine too. Current coderef already support insert coderef format at
right align even I'm in the middle of a line. I tested.

All your questions solved.

My wanted feature is simple, just `(insert (concat comment-char
coderef-format))`

[stardiviner]           <Hack this world!>      GPG key ID: 47C32433
IRC(freeenode): stardiviner                     Twitter:  @numbchild
Key fingerprint = 9BAA 92BC CDDD B9EF 3B36  CB99 B8C4 B8E5 47C3 2433
Blog: http://stardiviner.github.io/

On Wed, Jan 24, 2018 at 9:40 PM, Nicolas Goaziou <mail@nicolasgoaziou.fr>
wrote:

> Hello,
>
> "numbchild@gmail.com" <numbchild@gmail.com> writes:
>
> > I think this function should be in Org-mode itself.
> > Because when you're editing the source code, will not want this
> src-coderef
> > like `(ref:example)` be editable. It should be in comment.
>
> Thank you for the suggestion. However I have some doubts about this.
>
> What it the comment syntax is not properly defined? What if the coderef
> format already contains comment syntax? What if the language does not
> support inline comments and you're in the middle of a line (e.g.,
> FORTRAN)?
>
> I'm wondering if this is really a panacea. The current situation, albeit
> imperfect, is simple and easy to understand.
>
> WDYT?
>
> Regards,
>
> --
> Nicolas Goaziou
>