--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.dsl.processor/src/com/oracle/truffle/dsl/processor/ExpectError.java	Tue May 26 20:04:08 2015 +0200
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2015, 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.
+ *
+ * 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.
+ */
+package com.oracle.truffle.dsl.processor;
+
+import java.util.*;
+
+import javax.annotation.processing.*;
+import javax.lang.model.element.*;
+import javax.tools.Diagnostic.*;
+
+public class ExpectError {
+
+    public static void assertNoErrorExpected(ProcessingEnvironment processingEnv, Element element) {
+        TypeElement eee = processingEnv.getElementUtils().getTypeElement(TruffleTypes.EXPECT_ERROR_CLASS_NAME);
+        if (eee != null) {
+            for (AnnotationMirror am : element.getAnnotationMirrors()) {
+                if (am.getAnnotationType().asElement().equals(eee)) {
+                    processingEnv.getMessager().printMessage(Kind.ERROR, "Expected an error, but none found!", element);
+                }
+            }
+        }
+    }
+
+    public static boolean isExpectedError(ProcessingEnvironment processingEnv, Element element, String message) {
+        TypeElement eee = processingEnv.getElementUtils().getTypeElement(TruffleTypes.EXPECT_ERROR_CLASS_NAME);
+        if (eee != null) {
+            for (AnnotationMirror am : element.getAnnotationMirrors()) {
+                if (am.getAnnotationType().asElement().equals(eee)) {
+                    Map<? extends ExecutableElement, ? extends AnnotationValue> vals = am.getElementValues();
+                    if (vals.size() == 1) {
+                        AnnotationValue av = vals.values().iterator().next();
+                        if (av.getValue() instanceof List) {
+                            List<?> arr = (List<?>) av.getValue();
+                            for (Object o : arr) {
+                                if (o instanceof AnnotationValue) {
+                                    AnnotationValue ov = (AnnotationValue) o;
+                                    if (message.equals(ov.getValue())) {
+                                        return true;
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        return false;
+    }
+
+}