Unused global variable after modification

[orklah]

This would fix #6111 (comment)

This basically registers every global variable and prevent emitting UnusedVariable on those.

This means true positives (where UnusedVariable was emitted and the variable was not used) won't work anymore: https://psalm.dev/r/edb1c159ea. Hence the failing test here

However, this bring the behaviour closer to what already exists for references: https://psalm.dev/r/67292ae85a

Going beyond that would mean Psalm would have to record not only variable read access detecting usage but also write access. This seems a big piece of work for detecting a few globals and references unused.

If this is good enough to be merged, I'll remove the failing test and this will become the new behaviour for those cases.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/edb1c159ea

<?php

function scope(){
    global $a;
}

Psalm output (using commit 2127da3):

INFO: UnusedVariable - 4:12 - $a is never referenced or the value is not used

INFO: MissingReturnType - 3:10 - Method scope does not have a return type, expecting void

https://psalm.dev/r/67292ae85a

<?php

    function setProxySettingsFromEnv(string $ref): void
    {
		$ref2 = &$ref;   
    }

	function setProxySettingsFromEnv2(string &$ref): void
    {
		
    }

Psalm output (using commit 2127da3):

No issues!

[weirdan]

If this is good enough to be merged,

I think it is.

[orklah]

Thanks :)

Test is removed

[weirdan]

Thanks!