Re: [PHP-DEV] [Concept] declare(strict_identifiers=1)

Am 26.08.2026 um 21:57 schrieb Luca Rodenhäuser <[email protected]>:
> What it does solve, ordered by how much I think each is actually worth:
> 
> 1. PHP has no definition of an identifier. The only answer to "what is a
>    valid PHP identifier" is "whatever bytes the scanner accepted", which
>    is why the manual, PHP-Parser, every IDE and every static analyser
>    each copy out the same byte class. That is a language-definition gap,
>    not a bug report.

I'm not sure why you consider a formal definition like
	LABEL  [a-zA-Z_\x80-\xff][a-zA-Z0-9_\x80-\xff]*
not a definition. Personally I find this a simpler definition (and easier to implement in a parser) than something like
	UTF-8, UAX31-R1-2 with the standard Default-Ignorable Exclusion Profile

But then again I'm not really using non-ASCII identifiers today.

> 2. Identifiers that render identically are different identifiers. A
>    no-break space or a decomposed umlaut inside a name is invisible in
>    every editor. Real, but rare: 11 instances in 168,604 files.

I understand your point. But I'm not so worried about accidental mixups here. And this is also something an LSP or Linter can help you with if it a real concern for you.

> 3. Case-insensitive lookup folds ASCII only. Stra<U+00DF>e and
>    STRA<U+00DF>E are the same class; Stra<U+1E9E>e is not, and Strasse is
>    not. That rule is coherent only if identifiers are ASCII.

Case-insensitive folding adds another problem: Would you be using IntlChar::FOLD_CASE_DEFAULT or IntlChar::FOLD_CASE_EXCLUDE_SPECIAL_I to fold "I"? Or would you base it on a language setting?

In general I think most people consider the case-folding for identifiers nowadays to be a bug, not a feature, so I would probably rather try to reduce than extend it.

Regards,
- Chris