Fix misleading pass by reference error message

[kocsismate]

Currently, when a reference parameter is passed by value, the Argument #x ($y) cannot be passed by reference is written in the error message. This is utterly misleading, since I would assume that the argument mustn't be passed by reference. Now, this is fixed by using the must be passed by reference wording..

[Girgias]

I don't agree with the wording, the issue is that the thing being passed to the function parameter is a value for which a reference cannot be taken, as it's only variables that can be passed by references.

Your wording suggests that I should do something like change(&(list($val) = $array)) which is non sensical.

Better wording may be: Argument #1 ($ref) is a value and therefore cannot be passed by reference in %s:%d

[iluuu1994]

I guess the most clear would be something like Argument #x ($y) must be passable by reference, although I don't like that wording.

Argument #x ($y) cannot be passed by reference could be interpreted as "was passed by reference but shouldn't be", Argument #x ($y) must be passed by reference as "you need to do something to pass this value by reference", when that is done automatically by the engine.

[bwoebi]

Argument #x ($y) must be passed by reference, but the passed value could not be promoted to reference - something along these lines would be most clear I think: explaining the requirement and then why this fails. No need to be very concise here, error messages should be clear.

[Danack]

Maybe Argument #x ($y) must be a variable passed by reference (not a value) as the result needs to be storable in the reference, which can't be done with values in %s:%d

Also, light blue is a great colour.

[kocsismate]

How would Argument #x ($y) must be a variable in order to be able to pass it by reference sound to you? Is it unnatural/misleading?

Edit: maybe Argument #x ($y) must be a variable in order to pass it by reference?

[iluuu1994]

Is it accurate though? References can be created from properties or array DIMs too.

[kocsismate]

Is it accurate though? References can be created from properties or array DIMs too.

Duh. I'm out of ideas then..

[TimWolla]

Argument #1 (&$foo) is a reference parameter. The passed value is not writable and thus cannot be passed as a reference.

This suggestion specifically adds the & in front of the $ in the error message. In the first sentence it clearly states this fact once more. The second sentence explains why what the developer is doing is wrong. I'm open to more appropriate phrasing for the second sentence, but I believe the first one is good.

[iluuu1994]

"Temporary value cannot be used as a reference" might also be an option.

[internalsystemerror]

My 2 cents: must be referrable

[kocsismate]

What about Argument #x ($y) couldn't be passed by reference then? I think the past tense makes the problem clearer. Apart from this, I like George's suggestion the most: Argument #1 ($ref) is a value and therefore cannot be passed by reference.

[iluuu1994]

@kocsismate That sounds better, I'd just go for "could not" as we generally seem to avoid abbreviations.