Re: Has eval-and-compile changed in emacs 27?

[Stefan Monnier]

> Somehow I stumbled upon a fix by moving (eval-when-compile (require
> 'url-parse)) to after (require 'cl-lib) to get rid of the cl-reduce,
> cl-mapcan warnings in Emacs 27. But I never understand why. Any ideas?

That one's easy: the way the warning works is that when we process
a `eval-when-compile` we look at the `load-history` to see the functions
that have been defined during execution of its body, and then we remember
those as "only available now but maybe not at runtime".

If that loaded `cl-lib`, then a subsequent (require 'cl-lib) will be
a no-op and won't "unremember" the corresponding functions.


        Stefan