title: How to declare the type of a loop variable
body: <p>I want to do some integer arithmetic and was checking if SBCL could gain more speed if I provide explicit information about the <code>type</code> of values I use. While I easily could use <code>declare</code> in a <code>defun</code> or <code>let</code> directly to do so, I do not understand where to put the statement within a <code>loop</code> construct. </p>
  
  <p>I came across the documentation of the <code>iterate</code> package which offers such possibilities but wanted to stick to loop for the moment. </p>
  
  <p>A stub example could look like this:</p>
  
  <pre><code>(loop :for i from 1 upto 100 :collect
    (loop :for j from i upto 100
      :collect (* i j)))
  </code></pre>
  
  <p>How can I tell Lisp that <code>i</code> and <code>j</code> are e.g. of type <code>fixnum</code>?</p>