Throw on nested array in NodeTraverser

The AST never uses deeply nested arrays, so don't support this in
the node traverser. Throw an exception instead.

lib/PhpParser/NodeTraverser.php

@@ -162,12 +162,7 @@ class NodeTraverser implements NodeTraverserInterface
         $doNodes = array();
 
         foreach ($nodes as $i => &$node) {
-            if (is_array($node)) {
+            if ($node instanceof Node) {
-                $node = $this->traverseArray($node);
-                if ($this->stopTraversal) {
-                    break;
-                }
-            } elseif ($node instanceof Node) {
                 $traverseChildren = true;
                 foreach ($this->visitors as $visitor) {
                     $return = $visitor->enterNode($node);
@@ -204,6 +199,8 @@ class NodeTraverser implements NodeTraverserInterface
                         $node = $return;
                     }
                 }
+            } else if (is_array($node)) {
+                throw new \LogicException('Invalid node structure: Contains nested arrays');
             }
         }
 

test/PhpParser/NodeTraverserTest.php

@@ -115,16 +115,15 @@ class NodeTraverserTest extends \PHPUnit_Framework_TestCase
         );
     }
 
-    public function testDeepArray() {
+    /**
+     * @expectedException \LogicException
+     * @expectedExceptionMessage Invalid node structure: Contains nested arrays
+     */
+    public function testInvalidDeepArray() {
         $strNode = new String_('Foo');
         $stmts = array(array(array($strNode)));
 
-        $visitor = $this->getMockBuilder('PhpParser\NodeVisitor')->getMock();
-        $visitor->expects($this->at(1))->method('enterNode')->with($strNode);
-
         $traverser = new NodeTraverser;
-        $traverser->addVisitor($visitor);
-
         $this->assertEquals($stmts, $traverser->traverse($stmts));
     }