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

On 26-8-2026 21:42, [email protected] wrote:
> Not readability -- unambiguity. Three concrete things, no jargon:
>
> 1. Two identifiers that look identical on screen are currently two
>    different identifiers. $x and $x followed by U+00A0 NO-BREAK SPACE
>    are separate variables. So are "a" plus a combining diaeresis and the
>    single character U+00E4; both display as a-umlaut.
>
> 2. Text that is not valid UTF-8 at all is currently a valid identifier.
>    ${"\xFF\xFE"} = 1; compiles.
>
> 3. Nobody can state what a PHP identifier is except by copying the byte
>    class out of the scanner. The manual does exactly that, and so does
>    PHP-Parser.
>
> The declare says: in this file, an identifier is well-formed UTF-8, is a
> Unicode identifier in the sense of UAX #31 (the Unicode annex that
> defines this for programming languages), and is written in one canonical
> spelling. Anything else is a compile error.
>

Hi Luca & list,

Reading this and seeing you talk about making it a compile time error, 
raises the question for me of how this will interact with variable 
variables which don't comply with the proposed rules - AFAICS those 
wouldn't be able to be a compile time error and they also wouldn't have 
been found in the scan of Packagist files.
I imagine "on the fly" class creation, like when mocking code may also 
run into issues with this up to a point ?

Those are also the things which static analysis of code would not be 
able to find or flag (if this were left to static analysis).

Curious to hear your thoughts on this.

Smile,
Juliette