title: "do" multiple things in a function
body: <p><strong>I'm new.</strong></p>
  
  <p>So i got this working: </p>
  
  <pre><code>foo :: String -&gt; String
  foo s = do replace "aoa" "a" s
  </code></pre>
  
  <p><em>(Typing <code>foo "aoa"</code> returns <code>"a"</code>)</em><br>
  But when i add another replace: </p>
  
  <pre><code>foo :: String -&gt; String
  foo s = do replace "aoa" "a" s
             replace "uou" "u" s
  </code></pre>
  
  <p><em>(Typing <code>foo "aoa"</code> returns <code>"aoa"</code>)</em></p>
  
  <p>Everything breaks and i get this warning: </p>
  
  <pre><code>A do-notation statement discarded a result of type ‘Char’
  Suppress this warning by saying ‘_ &lt;- replace "aoa" "a" s’
  or by using the flag -fno-warn-unused-do-bind
  </code></pre>
  
  <p>Since i don't want to suppress the warning, this error message says nothing to me.</p>
  
  <p>What am i missing? </p>
  
  <p><strong>Edit1</strong><br>
  Examples:   </p>
  
  <pre><code>"aoaaoa" -&gt; "aa"   //Affected
  "uouaoa" -&gt; "ua"   //Affected
  "aua" -&gt; "aua"     //Not affected
  </code></pre>