I&#39;m seeing more strictness than I&#39;d expect for printf:<br><br>    &gt; printf &quot;foo %s\n&quot; (show ([1..10] ++ undefined))<br>    foo *** Exception: Prelude.undefined<br><br>In contrast,<br><br>    *Utils.Fabprim.ToHaskell&gt; &quot;foo &quot; ++ show ([1..10] ++ undefined) ++ &quot;\n&quot;<br>

    &quot;foo [1,2,3,4,5,6,7,8,9,10*** Exception: Prelude.undefined<br><br>Known issue?<br><br>-- Conal<br>