diff --git a/tests/expression/1.0/IExpression.hal b/tests/expression/1.0/IExpression.hal
index 4c38e5a7f1..a44e03c151 100644
--- a/tests/expression/1.0/IExpression.hal
+++ b/tests/expression/1.0/IExpression.hal
@@ -31,7 +31,7 @@ interface IExpression {
     noSuffixHex2 = 0x80000000,
     noSuffixHex3 = 0xffffffff,
     longHex1 = 0xffffffffl,
-    longHex2 = 0xfffffffff,
+    longHex2 = 0Xfffffffff,
     longHex3 = 0x7fffffffffffffff,
     longHex4 = 0x8000000000000000,
     longHex5 = 0xFFFFFFFFFFFFFFFF,