It looks like you are overflowing `Int` with 3^40.<div>In your QuickCheck test, the function signature uses Int:</div><div><br></div><div>prop_sanemodexp :: Int -> Int -> Int -> Property</div><div><br></div><div>Note:</div>
<div><div>Prelude> 3^40</div><div>12157665459056928801</div><div>Prelude> 3^40 :: Int</div><div>689956897</div><div><br></div><div><div>Prelude> 3^40 `mod` 3</div><div>0</div><div>Prelude> (3^40 `mod` 3) :: Int</div>
<div>1</div></div><div><br></div><div><br></div><div>L.</div><div><br></div><div><br></div><div><br></div><br><div class="gmail_quote">On Thu, May 31, 2012 at 5:35 PM, Clark Gaebel <span dir="ltr"><<a href="mailto:cgaebel@uwaterloo.ca" target="_blank">cgaebel@uwaterloo.ca</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><font face="verdana,sans-serif">*X> 3^40 `mod` 3 == modexp2 3 40 3<br>False<br>*X> modexp2 3 40 3<br>0<br>*X> 3^40 `mod` 3<br>
0<br><br>I'm confused. Last I checked, 0 == 0.<br><br>Using GHC 7.4.1, and the file x.hs (which has been loaded in ghci) can be found here: <a href="http://hpaste.org/69342" target="_blank">http://hpaste.org/69342</a><br>
<br>I noticed this after prop_sanemodexp was failing.<br><br>Any help would be appreciated,<br> - Clark</font>
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<br></blockquote></div><br></div>