title: Monomorphism Restriction, ghci, and let expression
body: <p>This expression is incorrect.</p>
  
  <pre><code>f = show
  </code></pre>
  
  <p>However, in <strong>ghci</strong> this is legit</p>
  
  <pre><code>let f = show
  </code></pre>
  
  <p>Moreover, its type is changed to</p>
  
  <pre><code>() -&gt; String
  </code></pre>
  
  <p>Is there any explanation of this phenomenon?</p>