On 04/02/2018 07:48 AM, Stefan Monnier wrote:
> we're not free to
> merge two strings just because they're `equal`, whereas for floats
> we are.
Yes, that's the key point here. I see that the Elisp documentation does 
not specify how eq behaves on floats with the same values, so I took a 
crack at specifying this the same way that Common Lisp and Scheme do by 
installing the attached into master. I doubt whether Common Lisp/Scheme 
semantics here will break real Elisp code in any significant way.