--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/truffle/com.oracle.truffle.api.dsl/src/com/oracle/truffle/api/dsl/TypeCheck.java	Wed Jun 17 10:58:08 2015 +0200
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2012, 2012, 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.
+ */
+package com.oracle.truffle.api.dsl;
+
+import java.lang.annotation.*;
+
+/**
+ * Overrides the standard way of checking for a certain type in a {@link TypeSystem}. This is useful
+ * for types where the guest language specific type check can be implemented more efficiently than a
+ * direct cast. The annotated method must be contained in a {@link TypeSystem} annotated class. Type
+ * checks must conform to the following signature: <code>public static boolean is{TypeName}(Object
+ * value)</code>. The checked type must be a type declared in the {@link TypeSystem}.
+ *
+ * <p>
+ * If no {@link TypeCheck} is declared then the type system implicitly uses a type check that can be
+ * declared as follows:
+ *
+ * <pre>
+ * {@literal @}TypeCheck(Type.class)
+ * public static boolean isType(Object value) {
+ *         return value instanceof Type;
+ * }
+ * </pre>
+ *
+ * @see TypeCast
+ */
+@Retention(RetentionPolicy.CLASS)
+@Target({ElementType.METHOD})
+public @interface TypeCheck {
+
+    Class<?> value();
+
+}