Christoph M. Becker

PHP 7.3 is [no longer actively supported](https://www.php.net/supported-versions.php), so won't receive bug fixes; fixing this for PHP 7.4 would constitute a BC break.

> doesn't fix in PHP 8 break BC? Yes, but some BC breaks are allowed in a major version.

See https://3v4l.org/t6uGK. I'd consider the `false` return being [undefined behavior](https://www.php.net/manual/en/functions.internal.php), similar to TypeErrors prior to PHP 8.0.0, but that might be debatable.

From the [PCRE docs](https://www.pcre.org/current/doc/html/pcre2unicode.html): > In addition to checking the format of the string, there is a check to ensure that all code points lie in the range U+0 to...

Java works with UTF-16, PHP' PCRE with UTF-8.

Comparing to the passed value won't necessarily work for sanitizing filters. You usually want to compare against `=== false`, unless you're using `FILTER_VALIDATE_BOOL`, in which case it might be best...

I have no problem with the way it is displayed now, and adding colors might even reduce legibility (see e.g. the menu with purple on black); but if you want...

> I think this looks much, much clearer. Maybe, but certainly not for some visually impaired people. Maybe it is a good idea to replace `true`/`false` here with some more...

So far, there [is only `ReflectionAttribute::IS_INSTANCEOF`](https://github.com/php/php-src/blob/cdf7240f7547b093aaee52e4fd0a2336f77e3374/ext/reflection/php_reflection.c#L1181-L1184). The meaning is [explained in the RFC](https://wiki.php.net/rfc/attributes_v2#reflection).

That has been added as part of fixing [bug 76104](https://bugs.php.net/bug.php?id=76104). Do you have a suggestion on how to improve this?