Handle static properties definition

src/main/php/PHPMD/Rule/AbstractLocalVariable.php

@@ -224,7 +224,7 @@ protected function getVariableImage($variable)
      *
      * @return \PDepend\Source\AST\ASTArtifact|\PDepend\Source\AST\ASTNode
      */
-    private function getNode($node)
+    protected function getNode($node)
     {
         if ($node instanceof ASTNode) {
             return $node->getNode();

src/main/php/PHPMD/Rule/CleanCode/UndefinedVariable.php

@@ -18,6 +18,7 @@
 namespace PHPMD\Rule\CleanCode;
 
 use PDepend\Source\AST\ASTArray;
+use PDepend\Source\AST\ASTClass;
 use PDepend\Source\AST\ASTPropertyPostfix;
 use PDepend\Source\AST\ASTUnaryExpression;
 use PDepend\Source\AST\ASTVariable;
@@ -55,9 +56,17 @@ public function apply(AbstractNode $node)
     {
         $this->images = array();
 
+        if ($node instanceof MethodNode) {
+            $this->collectProperties($this->getNode($node->getNode()->getParent()));
+        }
+
         $this->collect($node);
 
         foreach ($node->findChildrenOfType('Class') as $class) {
+            /** @var ASTClass $class */
+
+            $this->collectProperties($class);
+
             foreach ($class->getMethods() as $method) {
                 $this->collect(new MethodNode($method));
             }
@@ -67,6 +76,7 @@ public function apply(AbstractNode $node)
             if (!$this->isNotSuperGlobal($variable)) {
                 $this->addVariableDefinition($variable);
             }
+
             if (!$this->checkVariableDefined($variable, $node)) {
                 $this->addViolation($variable, array($this->getVariableImage($variable)));
             }
@@ -90,6 +100,19 @@ private function collect(AbstractNode $node)
         $this->collectGlobalStatements($node);
     }
 
+    private function collectProperties($node)
+    {
+        if (!($node instanceof ASTClass)) {
+            return;
+        }
+
+        foreach ($node->getProperties() as $property) {
+            if ($property->isStatic()) {
+                $this->images['::'.$property->getName()] = $property;
+            }
+        }
+    }
+
     /**
      * Stores the given literal node in an global of found variables.
      *

src/test/resources/files/Rule/CleanCode/UndefinedVariable/testRuleAppliesToStaticProperties.php

@@ -0,0 +1,24 @@
+<?php
+/**
+ * This file is part of PHP Mess Detector.
+ *
+ * Copyright (c) Manuel Pichler <mapi@phpmd.org>.
+ * All rights reserved.
+ *
+ * Licensed under BSD License
+ * For full copyright and license information, please see the LICENSE file.
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @author Manuel Pichler <mapi@phpmd.org>
+ * @copyright Manuel Pichler. All rights reserved.
+ * @license https://opensource.org/licenses/bsd-license.php BSD License
+ * @link http://phpmd.org/
+ */
+
+class testRuleAppliesToStaticProperties
+{
+    function testRuleAppliesToStaticProperties($key)
+    {
+        return static::$array[$key];
+    }
+}

src/test/resources/files/Rule/CleanCode/UndefinedVariable/testRuleDoesNotApplyToStaticProperties.php

@@ -17,6 +17,7 @@
 
 class testRuleDoesNotApplyToStaticProperties
 {
+    protected $foo = [];
     protected static $array = [];
 
     function testRuleDoesNotApplyToStaticProperties($key)
@@ -25,6 +26,6 @@ function testRuleDoesNotApplyToStaticProperties($key)
             return static::$array[$key];
         }
 
-        return static::$array[$key] = $key;
+        return $key;
     }
 }