diff --git a/tests/webtbs/tw1901.pp b/tests/webtbs/tw1901.pp
index 9d5545dc6e..1a25d56c20 100644
--- a/tests/webtbs/tw1901.pp
+++ b/tests/webtbs/tw1901.pp
@@ -9,9 +9,9 @@
 {$Q-}
 {$R-}
 
-const Inf=1/0;
-      NaN=0/0;
-      MinusInf=-Inf;
+const Inf=extended(1/0);
+      NaN=extended(0/0);
+      MinusInf=extended(-Inf);
 
 function make_str( tail: string ): string;
 var