Global variable falsely reported as never used

[cedric-anne]

Describe the bug
If inside a given context, e.g. a function, a global variable is set but never read, it is falsely reported as never used.

Describe the eclipse environment
Eclipse 2025-06
PDT 8.2

Describe your system

• OS: ubuntu
• Version 24.04

To Reproduce
2 warnings will be reported for the following code snippet:

• Variable '$A' is never used on line 9
• Variable '$C' is never used on line 9

<?php

namespace Foo;

class Bar
{
    public function doSomethingWithGlobals(): void
    {
        global $A, $B, $C;

        $A = new Bar();

        if ($B) {
            echo "azerty";
        }
    }
}

Expected behavior
The variable $A should not be considered as never used. Indeed it is a reference to the $A variable declared in the global scope and changing its value here has an impact outside the current context.

[zulus]

In general in this code global is just assigned, so is not used (no call, print, etc...), but globals are always tricky ;)

1. If I mark any imported variable as used by definition, also $C loose checking
2. If I mark any imported variable as used when appear in any statement (even assign-like), I loose validation of unused here, but for now might be enough:

$tmp = 1;
function() use($tmp) {
    $tmp = 2;
};

[cedric-anne]

In general in this code global is just assigned, so is not used (no call, print, etc...), but globals are always tricky ;)

1. If I mark any imported variable as used by definition, also $C loose checking
2. If I mark any imported variable as used when appear in any statement (even assign-like), I loose validation of unused here, but for now might be enough:

$tmp = 1;
function() use($tmp) {
$tmp = 2;
};

I do not know how PDT works, but IMHO, this issue is specific to global variables. I prefer having the current warnings on global variables that having no warnings on $tmp here.