> Hi everybody!
> Usually constant identifiers are treated case-sensitive in PHP. This is
> always the case for constants defined via a `const` declaration.
> However, define() allows to pass TRUE as third argument to define a
> case-insensitive constant. This feature appears to potentially result
> in confusion, and also causes bugs as shown in
> <https://bugs.php.net/74450>. See an example created by Nikita to see
> some probably unexpected behavior: <https://3v4l.org/L6nCp>.
> Even if these issues could be resolved, I still think allowing both
> case-sensitive and case-insensitive constant identifiers does more harm
> than good, so either case-sensitive or case-insensitive constant
> identifiers should be removed from the language. Since case-sensitive
> constant identifiers are already the default, and HHVM doesn't even
> support case-insensitive identifiers at all, I would suggest to remove
> case-insensitive constant identifiers.
> This could be implemented by triggering E_DEPRECATED whenever the third
> argument to define() is TRUE in PHP 7.3, and to remove this parameter
> altogether in PHP 8. Most likely some further simplification in the
> engine could be done then as well.