title: Haskell bitwise operators in Data.Bits
body: <p>I am new to Haskell and am trying to use bitwise operations from Data.Bits.  Every time I try I get an error message</p>
  
  <pre><code>Prelude Data.Bits&gt; 1 `shiftL` 16
  
  &lt;interactive&gt;:1:0:
      Ambiguous type variable `t' in the constraint:
        `Bits t' arising from a use of `shiftL' at &lt;interactive&gt;:1:0-12
      Probable fix: add a type signature that fixes these type variable(s)
  </code></pre>
  
  <p>This happens for a number of operations, I also tried .|. and .&amp;.</p>
  
  <p>I must be missing something very simple, please let me know if you can spot the problem</p>