title: Monad reader and partial application of functions
body: <p>Since partially applied functions <a href="https://github.com/purescript/purescript-transformers/blob/v2.2.0/src/Control/Monad/Reader/Class.purs#L41" rel="nofollow noreferrer">are instances of the <code>MonadReader</code></a>, why is the following code incorrect?</p>
  
  <pre><code>runReader (\x -&gt; x + 2) 4 
  </code></pre>
  
  <p>or even </p>
  
  <pre><code>runReader (\x -&gt; pure $ x + 2) 4
  </code></pre>