title: Why can I not install haskell Slides package?
body: <p>Attempting to install Haskell's <a href="https://hackage.haskell.org/package/Slides" rel="nofollow">Slides</a> package, I run into cabal hell:</p>
  
  <pre><code>$ cabal update &amp;&amp; cabal install slides
  Downloading the latest package list from hackage.haskell.org
  Resolving dependencies...
  cabal: Could not resolve dependencies:
  trying: Slides-0.1.0.8 (user goal)
  next goal: base (dependency of Slides-0.1.0.8)
  rejecting: base-4.9.0.0/installed-4.9... (conflict: Slides =&gt; base&gt;=4.8 &amp;&amp;
  &lt;4.9)
  rejecting: base-4.9.0.0, base-4.8.2.0, base-4.8.1.0, base-4.8.0.0,
  base-4.7.0.2, base-4.7.0.1, base-4.7.0.0, base-4.6.0.1, base-4.6.0.0,
  base-4.5.1.0, base-4.5.0.0, base-4.4.1.0, base-4.4.0.0, base-4.3.1.0,
  base-4.3.0.0, base-4.2.0.2, base-4.2.0.1, base-4.2.0.0, base-4.1.0.0,
  base-4.0.0.0, base-3.0.3.2, base-3.0.3.1 (constraint from non-upgradeable
  package requires installed instance)
  Dependency tree exhaustively searched.
  </code></pre>
  
  <p>I reset my packages by running:</p>
  
  <pre><code>$ rm -rf ~/.ghc ~/.cabal
  </code></pre>
  
  <p>per the instructions <a href="https://www.schoolofhaskell.com/user/simonmichael/how-to-cabal-install#could-not-resolve-dependencies--cabal-hell" rel="nofollow">here</a>, but still get that same error. Not sure what to try next.</p>