title: multiple assignment of concurrent statement
body: <p>The following code gives me an error, which I can't figure out myself.
  The error is because there are multiple assignments of output d0 </p>
  
  <pre><code>do: for i in 0 to 9 generate
    d0&lt;=di0(129-i downto 120-i)
         when f(i)='1';
  end generate do;
  </code></pre>