# HG changeset patch
# User Michael Van De Vanter  <michael.van.de.vanter@oracle.com>
# Date 1431480412 25200
# Node ID 19801a65cf571ded902306e64f74d25b88006a3d
# Parent  acfc5e32e6782ab3b32c2297258fcf0de9728a7d
Truffle/Instrumentation:  NPE guard

diff -r acfc5e32e678 -r 19801a65cf57 graal/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/Instrument.java
--- a/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/Instrument.java	Tue May 12 18:04:53 2015 -0700
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/Instrument.java	Tue May 12 18:26:52 2015 -0700
@@ -466,7 +466,10 @@
                 if (requiredResultType == null) {
                     return;
                 }
-                if (result == null || !(requiredResultType.isAssignableFrom(result.getClass()))) {
+                if (result == null) {
+                    throw new RuntimeException("Instrument result null: " + requiredResultType.getSimpleName() + " is required");
+                }
+                if (!(requiredResultType.isAssignableFrom(result.getClass()))) {
                     throw new RuntimeException("Instrument result " + result.toString() + " not assignable to " + requiredResultType.getSimpleName());
                 }
             }