"Cannot declare xxx because the name is already in use" is broken with NS

[mvorisek]

Description

The following code:

<?php

namespace Ns;

use Ns\Foo;

class Foo {}

Resulted in this output:

(no output/error)

But I expected this output instead:

Fatal error: Cannot declare class Foo because the name is already in use

Without namespace, the error is emit as expected - https://3v4l.org/DAT52, but when namespace is declared, the error is not emit even if the the same use/import statement is present - https://3v4l.org/tt1sL.

As the declared Foo class masks the use/import the same way, I would expect an error to be emit in both cases.

PHP Version

any

Operating System

any

[damianwadley]

You're "importing" the exact thing you're defining. It's a bit silly, sure, but why should it be an error?

[mvorisek]

Because "masked" import is useless and it means more or less typo in the code. I am reporting it mainly as when no namespace is defined, an error is emit, so there is something inconsistent in php-src and I would expect error in both cases (/wo and /w namespace).

[damianwadley]

There's no inconsistency here: if you try to import a thing with a fully-qualified name of X and then declare a thing with a fully-qualified name of X then there is no error. What you're seeing as "inconsistent" is because one of the examples follows the rule and the other does not.

These are not errors because the (fully-qualified) imported and defined names are the same:

use Foo; // there is a warning for this pointless statement, though

class Foo { } // imported Foo, defining Foo

namespace Ns;

use Ns\Foo;

class Foo { } // imported Ns\Foo, defining Ns\Foo

These two are errors because the (fully-qualified) imported and defined names are not the same:

use Ns\Foo;

class Foo { } // cannot define Foo because Ns\Foo is being used

namespace Ns;

use Foo;

class Foo { } // cannot define Ns\Foo because Foo is being used

[iluuu1994]

use is just a way to say "when I refer to Foo in this file, I really mean Ns\Foo". It's not a definition. Sure, it's completely useless, but so is this:

namespace Ns;
use Ns\Foo; // Useless, Bar already refers to Ns\Foo
new Foo();

There was actually a PR that asked to remove a related warning (#12949), so I don't think introducing more warnings is useful.

[github-actions]

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