Re: Warning on files byte-compiled with different versions

[Stefan Monnier]

> contains multi-byte characters.  Just because the file was compiled by a
> later version should not be a reason to prevent loading it, only if the
> format itself changes.

In practice, it's common to bump into problems for a file compiled with
a later version.  Usually it's because of macros, tho there are other
cases (e.g. the new bytecodes in 24.1 used for lexical-binding code, or
the new byte-codes (introduced in 24.4 and used since 25.1) used to
compile condition-case more efficiently in lexical-binding).

It's just much easier to say there's no forward compatibility, even if
it will sometime work fine.  Note also that we're talking
about signaling a warning, not an error.


        Stefan