--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.api.dsl.test/src/com/oracle/truffle/api/dsl/test/ReachabilityTest.java	Mon Aug 11 15:53:05 2014 +0200
@@ -0,0 +1,353 @@
+package com.oracle.truffle.api.dsl.test;
+
+import java.math.*;
+
+import com.oracle.truffle.api.dsl.*;
+import com.oracle.truffle.api.dsl.test.TypeSystemTest.*;
+
+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;
+        }
+
+    }
+
+    @NodeAssumptions({"a1"})
+    static class ReachabilityAssumption1 extends ValueNode {
+
+        @Specialization(assumptions = "a1")
+        int do2() {
+            return 1;
+        }
+
+        @Specialization
+        int do1() {
+            return 2;
+        }
+
+    }
+
+    @NodeAssumptions({"a1"})
+    static class ReachabilityAssumption2 extends ValueNode {
+
+        @Specialization(assumptions = "a1")
+        int do2() {
+            return 1;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2().")
+        @Specialization(assumptions = "a1")
+        int do1() {
+            return 2;
+        }
+
+    }
+
+    @NodeAssumptions({"a1", "a2"})
+    static class ReachabilityAssumption3 extends ValueNode {
+
+        @Specialization(assumptions = {"a1", "a2"})
+        int do2() {
+            return 1;
+        }
+
+        @Specialization(assumptions = "a1")
+        int do1() {
+            return 2;
+        }
+
+    }
+
+    @NodeAssumptions({"a1", "a2"})
+    static class ReachabilityAssumption4 extends ValueNode {
+
+        @Specialization(assumptions = "a1")
+        int do2() {
+            return 1;
+        }
+
+        @Specialization(assumptions = "a2")
+        int do1() {
+            return 2;
+        }
+
+    }
+
+    @NodeAssumptions({"a1", "a2"})
+    static class ReachabilityAssumption5 extends ValueNode {
+
+        @Specialization
+        int do2() {
+            return 1;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2().")
+        @Specialization(assumptions = "a2")
+        int do1() {
+            return 2;
+        }
+
+    }
+
+    @NodeAssumptions({"a1", "a2"})
+    static class ReachabilityAssumption6 extends ValueNode {
+
+        @Specialization(assumptions = {"a1"})
+        int do2() {
+            return 1;
+        }
+
+        @ExpectError("Specialization is not reachable. It is shadowed by do2().")
+        @Specialization(assumptions = {"a1", "a2"})
+        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;
+        }
+
+    }
+
+}