8195829: Parsing a nameless ES6 class results in a thrown NullPointerException

Reviewed-by: jlaskey, hannesw

src/jdk.scripting.nashorn/share/classes/jdk/nashorn/api/tree/IRTranslator.java

@@ -473,9 +473,9 @@ final class IRTranslator extends SimpleNodeVisitor {
     @Override
     public boolean enterClassNode(final ClassNode classNode) {
         assert !classNode.isStatement(): "should not reach here for class declaration";
-
+        final IdentNode className = classNode.getIdent();
         curExpr = new ClassExpressionTreeImpl(classNode,
-            translateIdent(classNode.getIdent()),
+            className != null? translateIdent(className) : null,
             translateExpr(classNode.getClassHeritage()),
             translateProperty(classNode.getConstructor()),
             translateProperties(classNode.getClassElements()));

test/nashorn/script/basic/JDK-8195829.js

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * JDK-8195829 : Parsing a nameless ES6 class results in a thrown NullPointerException.
+ *
+ * @test
+ * @run
+ */
+
+var Parser = Java.type("jdk.nashorn.api.tree.Parser");
+var SimpleTreeVisitor = Java.type("jdk.nashorn.api.tree.SimpleTreeVisitorES6");
+var parser = Parser.create("--language=es6"); 
+var ast = parser.parse("test.js", "(class {});", print);
+var reachedClassExpr = false;
+ast.accept(new (Java.extend(SimpleTreeVisitor)) {
+    visitClassExpression: function(node, extra) {
+        reachedClassExpr = true;
+        Assert.assertTrue(node.name === null);
+    }
+}, null);
+
+Assert.assertTrue(reachedClassExpr);
+