add AssignmentExpression

Node/AssignmentExpression.php

@@ -0,0 +1,29 @@
+<?php
+/*---------------------------------------------------------------------------------------------
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+namespace PhpParser\Node;
+
+use PhpParser\NodeKind;
+use PhpParser\Token;
+
+class AssignmentExpression extends BinaryExpression {
+
+    /** @var Expression */
+    public $leftOperand;
+
+    /** @var Token */
+    public $operator;
+
+    /** @var Token */
+    public $byRef;
+
+    /** @var Expression */
+    public $rightOperand;
+
+    public function __construct() {
+        parent::__construct(NodeKind::AssignmentExpression);
+    }
+}