Indicates whether a variable is global

[cedric-anne]

This will permit to easilly assign types to global variables in an extension. Without this change, it is not possible to distinguish local variables from global variables.

Related to phpstan/phpstan#13243 and following a discussion in #4233.

Here is an exemple:

<?php

namespace MyPhpstanExtension;

use PhpParser\Node\Expr;
use PhpParser\Node\Expr\Variable;
use PHPStan\Analyser\Scope;
use PHPStan\Type\ObjectType;
use PHPStan\Type\ExpressionTypeResolverExtension;
use PHPStan\Type\Type;

class GlobalExpressionTypeResolverExtension implements ExpressionTypeResolverExtension
{

	public function getType(Expr $expr, Scope $scope): ?Type
	{
		if (!$expr instanceof Variable || !$scope->isGlobalVariable($expr->name)) {
			return null;
		}

		if ($expr->name === 'DB') {
			return new ObjectType(\App\Db::class);
		}

		return null;
	}
}