Implement MagicClassConstantRule

[staabm]

closes phpstan/phpstan#10099

background: https://www.php.net/manual/en/language.constants.magic.php

[ondrejmirtes]

This should be enabled only with bleeding edge. The code does not error, it just returns an empty string AFAIK.

[staabm]

I have used a feature flag with a more general name, so I can use it for similar rules for __FUNCTION__ and __METHOD__

[ondrejmirtes]

The message should be different. It just returns an empty string.

[ondrejmirtes]

Can you also please go through other magic constants and report them when used in a wrong way? Maybe it can all be done inside this single rule.

[staabm]

there is one interessting leftover case:

// test.php
function doFooParams(
	string $file = __FILE__,
	int $line = __LINE__,
	string $class = __CLASS__,
	string $dir = __DIR__,
	string $namespace = __NAMESPACE__,
	string $method = __METHOD__,
	string $function = __FUNCTION__,
	string $trait = __TRAIT__
): void
{
}

since used in the parameter-list and not the function body it false-positives with

https://3v4l.org/BbZWn

$ php bin/phpstan analyze test.php --debug
Note: Using configuration file C:\dvl\Workspace\phpstan-src\phpstan.neon.dist.
C:\dvl\Workspace\phpstan-src\test.php
 ------ -----------------------------------------------------------------------------
  Line   test.php
 ------ -----------------------------------------------------------------------------
  6      Magic constant __CLASS__ is always empty when used outside a class.
  8      Magic constant __NAMESPACE__ is always empty when used in global namespace.
  9      Magic constant __METHOD__ is always empty when used outside a function.
  10     Magic constant __FUNCTION__ is always empty when used outside a function.
 ------ -----------------------------------------------------------------------------

[staabm]

we could fix the above case by moving enterFunction before the processParamNode call in

phpstan-src/src/Analyser/NodeScopeResolver.php

Lines 451 to 459 in 231ed3e

	foreach ($stmt->params as $param) {
	$this->processParamNode($param, $scope, $nodeCallback);
	}
	if ($stmt->returnType !== null) {
	$nodeCallback($stmt->returnType, $scope);
	}
	$functionScope = $scope->enterFunction(

wdyt?

[staabm]

Instead of changing NodeScopeResolver I went with adding a dedicated new NodeVisitor to prevent the false positives

[ondrejmirtes]

Please deleted "when used" from all messages. They'll still make sense.

[ondrejmirtes]

"outside a trait"

[staabm]

(btw: interessting that issuebot did not realize that the snippet from issue phpstan/phpstan#10099 gets a new error with this PR - locally it works as expected though)

[ondrejmirtes]

This doesn't seem right. What about private $foo = __METHOD__;?

Also a false positive here - you can have an anonymous function outside a class/function and it's going to report '{closure}'.

[ondrejmirtes]

Thank you.