diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalTypeId.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalTypeId.java
index 1d56670dd21..fad9747c5c1 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalTypeId.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/semantics/EvalTypeId.java
@@ -42,6 +42,7 @@ import org.eclipse.cdt.internal.core.dom.parser.DependentValue;
 import org.eclipse.cdt.internal.core.dom.parser.ITypeMarshalBuffer;
 import org.eclipse.cdt.internal.core.dom.parser.IntegralValue;
 import org.eclipse.cdt.internal.core.dom.parser.SizeofCalculator;
+import org.eclipse.cdt.internal.core.dom.parser.SizeofCalculator.SizeAndAlignment;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPFunction;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.CPPPointerType;
 import org.eclipse.cdt.internal.core.dom.parser.cpp.ClassTypeHelper;
@@ -195,15 +196,18 @@ public class EvalTypeId extends CPPDependentEvaluation {
 				// Cast signed integer to unsigned.
 				Long val = argVal.numberValue().longValue();
 				if (val < 0 && inputType instanceof ICPPBasicType && ((ICPPBasicType) inputType).isUnsigned()) {
-					long sizeof = SizeofCalculator.getSizeAndAlignment(inputType).size;
-					if (sizeof > 4) {
-						// Java's "long" can't represent the full range of an 64-bit unsigned integer
-						// in C++.
-						sizeof = 4;
+					SizeAndAlignment sizeAndAlignment = SizeofCalculator.getSizeAndAlignment(inputType);
+					if (sizeAndAlignment != null) {
+						long sizeof = sizeAndAlignment.size;
+						if (sizeof > 4) {
+							// Java's "long" can't represent the full range of an 64-bit unsigned integer
+							// in C++.
+							sizeof = 4;
+						}
+						long range = (1L << (sizeof * 8 - 1));
+						val += range;
+						return IntegralValue.create(val);
 					}
-					long range = (1L << (sizeof * 8 - 1));
-					val += range;
-					return IntegralValue.create(val);
 				}
 			}
 			return argVal;