diff --git a/Rez/Expression.cc b/Rez/Expression.cc
index 6994541c39..636f6e8547 100644
--- a/Rez/Expression.cc
+++ b/Rez/Expression.cc
@@ -110,6 +110,9 @@ int UnaryExpr::evaluateInt(ResourceCompiler *ctx)
 			return -a->evaluateInt(ctx);
 		case UnaryOp::COMPLEMENT:
 			return ~a->evaluateInt(ctx);
+		default:
+			throw TypeError();
+			break;
 	}
 }