--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/truffle/com.oracle.truffle.api.dsl.test/src/com/oracle/truffle/api/dsl/test/ReachabilityTest.java	Wed Jun 17 10:58:08 2015 +0200
@@ -0,0 +1,284 @@
+/*
+ * 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.
+ *
+ * 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.test;
+
+import java.math.*;
+
+import com.oracle.truffle.api.dsl.*;
+import com.oracle.truffle.api.dsl.test.TypeSystemTest.Abstract;
+import com.oracle.truffle.api.dsl.test.TypeSystemTest.BExtendsAbstract;
+import com.oracle.truffle.api.dsl.test.TypeSystemTest.ValueNode;
+
+public class ReachabilityTest {
+
+    static class Reachability1 extends ValueNode {
+        @Specialization
+        int do2() {
+            return 2;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2().")
+        @Specialization
+        int do1() {
+            return 2;
+        }
+    }
+
+    @NodeChildren({@NodeChild("a")})
+    static class ReachabilityType1 extends ValueNode {
+        @Specialization
+        int do2(int a) {
+            return a;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2(int).")
+        @Specialization
+        int do1(int a) {
+            return a;
+        }
+    }
+
+    @NodeChildren({@NodeChild("a")})
+    static class ReachabilityType2 extends ValueNode {
+        @Specialization
+        BExtendsAbstract do2(BExtendsAbstract a) {
+            return a;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2(BExtendsAbstract).")
+        @Specialization
+        BExtendsAbstract do1(BExtendsAbstract a) {
+            return a;
+        }
+    }
+
+    @NodeChildren({@NodeChild("a")})
+    static class ReachabilityType3 extends ValueNode {
+        @Specialization
+        Abstract do2(Abstract a) {
+            return a;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2(Abstract).")
+        @Specialization
+        BExtendsAbstract do1(BExtendsAbstract a) {
+            return a;
+        }
+    }
+
+    @NodeChildren({@NodeChild("a")})
+    static class ReachabilityType4 extends ValueNode {
+
+        @Specialization
+        BExtendsAbstract do2(BExtendsAbstract a) {
+            return a;
+        }
+
+        @Specialization
+        Abstract do1(Abstract a) {
+            return a;
+        }
+
+    }
+
+    @NodeChildren({@NodeChild("a")})
+    static class ReachabilityType5 extends ValueNode {
+
+        @Specialization
+        double do2(double a) {
+            return a;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2(double).")
+        @Specialization
+        int do1(int a) {
+            return a;
+        }
+
+    }
+
+    @NodeChildren({@NodeChild("a")})
+    static class ReachabilityType6 extends ValueNode {
+
+        @Specialization
+        BigInteger do2(BigInteger a) {
+            return a;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2(BigInteger).")
+        @Specialization
+        int do1(int a) {
+            return a;
+        }
+
+    }
+
+    @NodeChildren({@NodeChild("a")})
+    static class ReachabilityType7 extends ValueNode {
+
+        @Specialization
+        int do2(int a) {
+            return a;
+        }
+
+        @Specialization
+        BigInteger do1(BigInteger a) {
+            return a;
+        }
+
+    }
+
+    @NodeChildren({@NodeChild("a")})
+    static class ReachabilityType8 extends ValueNode {
+
+        @Specialization
+        int do2(int a) {
+            return a;
+        }
+
+        @Specialization
+        Object do1(Object a) {
+            return a;
+        }
+
+    }
+
+    @NodeChildren({@NodeChild("a")})
+    static class ReachabilityType9 extends ValueNode {
+
+        @Specialization
+        Object do2(Object a) {
+            return a;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2(Object).")
+        @Specialization
+        int do1(int a) {
+            return a;
+        }
+    }
+
+    static class ReachabilityGuard1 extends ValueNode {
+
+        boolean foo() {
+            return false;
+        }
+
+        @Specialization(guards = "foo()")
+        int do2() {
+            return 1;
+        }
+
+        @Specialization
+        int do1() {
+            return 2;
+        }
+
+    }
+
+    static class ReachabilityGuard2 extends ValueNode {
+
+        boolean foo() {
+            return false;
+        }
+
+        @Specialization
+        int do2() {
+            return 2;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2().")
+        @Specialization(guards = "foo()")
+        int do1() {
+            return 1;
+        }
+
+    }
+
+    static class ReachabilityGuard3 extends ValueNode {
+
+        boolean foo() {
+            return false;
+        }
+
+        @Specialization(guards = "foo()")
+        int do2() {
+            return 1;
+        }
+
+        @Specialization
+        int do1() {
+            return 2;
+        }
+
+    }
+
+    static class ReachabilityGuard4 extends ValueNode {
+
+        boolean foo() {
+            return false;
+        }
+
+        @Specialization(guards = "foo()")
+        int do2() {
+            return 1;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2().")
+        @Specialization(guards = "foo()")
+        int do1() {
+            return 2;
+        }
+
+    }
+
+    static class ReachabilityThrowable1 extends ValueNode {
+
+        @Specialization(rewriteOn = RuntimeException.class)
+        int do2() throws RuntimeException {
+            return 1;
+        }
+
+        @Specialization
+        int do1() {
+            return 2;
+        }
+
+    }
+
+    static class ReachabilityThrowable2 extends ValueNode {
+
+        @Specialization
+        int do2() {
+            return 1;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2().")
+        @Specialization(rewriteOn = RuntimeException.class)
+        int do1() throws RuntimeException {
+            return 2;
+        }
+
+    }
+
+}