[pwdisswordfishy]

And how is Closure::fromCallable('trim') recommended by the article any better in that respect?

    $ php8.4 -r "var_dump(Closure::fromCallable('trim') === Closure::fromCallable('trim'));"
    bool(false)

[joe_hoyle]

It is not better, this is a problem with the first-class callable syntax altogether.