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<div dir="ltr" data-setdir="false">This is what I was going to say. The original poster is right, but still, null is a function. It is one level of indirection away from pattern matching.</div><div dir="ltr" data-setdir="false"><br></div><div><br></div>
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On Tuesday, April 16, 2024 at 10:46:56 AM EDT, Henning Thielemann <lemming@henning-thielemann.de> wrote:
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<div><div dir="ltr"><div class="yqt1516291836" id="yqtfd06107"><br clear="none">On Tue, 16 Apr 2024, George Colpitts wrote:<br clear="none"><br clear="none">> ghc should be able to deduce correct use of partial functions and not give a warning in such cases, e.g.<br clear="none">> in 9.8.2<br clear="none">> <br clear="none">> if null ys then [] else [(xs,tail ys)])<br clear="none">> <br clear="none">> gets a warning<br clear="none">> <br clear="none">> warning: [GHC-63394] [-Wx-partial]<br clear="none">> <br clear="none">> but it is clear that this use of tail will never be a problem so IMHO that line of code should not get a<br clear="none">> warning. <br clear="none">> <br clear="none">> Does anybody know if there is a plan or enhancement request to eliminate such warnings? </div><br clear="none"><br clear="none"><br clear="none">I would just use good old pattern matching:<br clear="none"><br clear="none">case ys of<br clear="none"> [] -> []<br clear="none"> _:zs -> [(xs,zs)]</div><div class="yqt1516291836" id="yqtfd43726">_______________________________________________<br clear="none">Haskell-Cafe mailing list<br clear="none">To (un)subscribe, modify options or view archives go to:<br clear="none"><a shape="rect" href="http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe" target="_blank">http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe</a><br clear="none">Only members subscribed via the mailman list are allowed to post.</div></div>
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