<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Jan 26, 2015 at 4:54 PM, Bertram Felgenhauer <span dir="ltr"><<a href="mailto:bertram.felgenhauer@googlemail.com" target="_blank">bertram.felgenhauer@googlemail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span class="">Tom Murphy wrote:<br>
> So it's the "(rigid, skolem)" error you sometimes happen across. The code<br>
> that's causing it, though, is pretty unsuspicious:<br>
<br>
</span>Just two clues, pointing towards `b` being monomorphic as one<br>
ontributing factor:<br>
<br>
* adding {-# LANGUAGE NoMonoLocalBinds #-} works.<br>
* giving `b` a standalone type signature makes it work, that is:<br><span class="">(...)<br>
</span>I'm not sure how enabling GADTs affects type-checking here.<br></blockquote><div><br></div><div>See  <a href="https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/other-type-extensions.html#mono-local-binds">https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/other-type-extensions.html#mono-local-binds</a></div><div><br></div><div>In particular:</div><div>"<span style="color:rgb(0,0,0);font-family:sans-serif;font-size:medium">The flag </span><code class="" style="color:rgb(0,0,0)">-XMonoLocalBinds</code><span style="color:rgb(0,0,0);font-family:sans-serif;font-size:medium"> is implied by </span><code class="" style="color:rgb(0,0,0)">-XTypeFamilies</code><span style="color:rgb(0,0,0);font-family:sans-serif;font-size:medium"> and </span><code class="" style="color:rgb(0,0,0)">-XGADTs</code><span style="color:rgb(0,0,0);font-family:sans-serif;font-size:medium">. You can switch it off again with </span><code class="" style="color:rgb(0,0,0)">-XNoMonoLocalBinds</code><span style="color:rgb(0,0,0);font-family:sans-serif;font-size:medium"> but type inference becomes less predicatable if you do so."</span></div></div><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div>brandon s allbery kf8nh                               sine nomine associates</div><div><a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.com</a>                                  <a href="mailto:ballbery@sinenomine.net" target="_blank">ballbery@sinenomine.net</a></div><div>unix, openafs, kerberos, infrastructure, xmonad        <a href="http://sinenomine.net" target="_blank">http://sinenomine.net</a></div></div></div>
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