diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcodeCPort/slghpatexpress/OperandValue.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcodeCPort/slghpatexpress/OperandValue.java
index 6b47450fb5..63fce1db89 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcodeCPort/slghpatexpress/OperandValue.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcodeCPort/slghpatexpress/OperandValue.java
@@ -1,6 +1,5 @@
 /* ###
  * IP: GHIDRA
- * REVIEWED: YES
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +15,10 @@
  */
 package ghidra.pcodeCPort.slghpatexpress;
 
+import java.io.PrintStream;
+
+import org.jdom.Element;
+
 import generic.stl.VectorSTL;
 import ghidra.pcodeCPort.context.*;
 import ghidra.pcodeCPort.sleighbase.SleighBase;
@@ -25,10 +28,6 @@ import ghidra.pcodeCPort.utils.MutableInt;
 import ghidra.pcodeCPort.utils.XmlUtils;
 import ghidra.sleigh.grammar.Location;
 
-import java.io.PrintStream;
-
-import org.jdom.Element;
-
 public class OperandValue extends PatternValue {
 
 	private int index; // This is the defining field of expression
@@ -50,6 +49,9 @@ public class OperandValue extends PatternValue {
 
 	@Override
 	public TokenPattern genMinPattern(VectorSTL<TokenPattern> ops) {
+		if (index >= ops.size()) {
+			return null;
+		}
 		return ops.get(index);
 	}
 
diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcodeCPort/slghsymbol/Constructor.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcodeCPort/slghsymbol/Constructor.java
index 3e3d7d0b09..69b52932a9 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcodeCPort/slghsymbol/Constructor.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/pcodeCPort/slghsymbol/Constructor.java
@@ -571,7 +571,11 @@ public class Constructor {
 				}
 			}
 			else if (defexp != null) {
-				oppattern.push_back(defexp.genMinPattern(oppattern));
+				TokenPattern tmppat = defexp.genMinPattern(oppattern);
+				if (null == tmppat) {
+					throw new SleighError("operand " + sym.getName() + " has an issue", location);
+				}
+				oppattern.push_back(tmppat);
 			}
 			else {
 				throw new SleighError("operand " + sym.getName() + " is undefined", location);