irb warning: "can't alias ls from irb_ls." should perhaps not lead to a warning for vanilla ruby code

[rubyFeedback]

Take the following content of irbrc:

---

def ll                   
  pp Dir.pwd             
end                      
                     
alias ls ll

---

irb shows this warning:

irb: warn: can't alias ls from irb_ls.

I am not sure whether that warning should show. I understand that
aycabta wanted to make irb nicer to use, and he succeeded - no
doubt. The modern irb is much better than the oldschool irb, tons
more features and so forth.

But I believe we ruby users should be able to do something
such as "alias ls any_method_name". IRB should ideally
simulate vanilla ruby as much as possible, so that warning is
a bit strange. I would suggest to not show the warning.

It is not a big issue since it is just a warning, but I just ran into
this problem. In my project (gem called roebe) I carry my own
irbrc, where I tap into all my other ruby code. One method
call is "ll", which is a wrapper over a class that displays the
content of a directory in a colourized manner. Because I am
forgetful and I hate having to remember something, I use
tons of aliases, and "ls" is one such alias that i use.

I hope my use case description is useful. I am not necessarily
suggesting any change have to be made! It is ok to close this
issue either way. But I wanted to let aycabta know that there
are real use cases. Perhaps if you want to change it for a
later time, we could have different "profiles" or something,
such as:

"vanilla irb" tries to be as much ruby as possible
"feature-rich irb" can have the current behaviour, and so
forth. But anyway, I report this just to let aycabta and the
ruby core team know - you guys can proceed how you want
to, and please do feel free to close this issue at any moment
in time as well. Thank you for reading.

[tompng]

Fixed in irb 1.13.0 #824