UselessFunctionReturnValueRule: More precise error message

[staabm]

closes phpstan/phpstan#11377

[phpstan-bot]

This pull request has been marked as ready for review.

[takaram]

highlight_string never returns false while its return type is declared as string|bool
PHP 8.4 is going to change it to string|true.
https://github.com/php/php-src/blob/php-8.4.0alpha2/NEWS#L26-L27

highlight_file and show_source may return both true and false, but it means that using the return value is not useless, doesn't it?

[staabm]

highlight_file and show_source may return both true and false, but it means that using the return value is not useless, doesn't it?

I am not sure. this might mean we should drop these 2 from the rule

[ondrejmirtes]

Yes, highlight_file and show_source should be dropped from this rule. It's more complicated with them.

Instead, these functions could have a stub file with a conditional return type.

Then, someone is free to write a rule that disallows bool and potentially other types to be used in a string context, like concat and others. (But it's a bad fit for PHPStan core because it's not a bug.)

[staabm]

Yes, highlight_file and show_source should be dropped from this rule. It's more complicated with them.

done

Instead, these functions could have a stub file with a conditional return type.

we already have these stubs

[ondrejmirtes]

Thank you.