title: Using let! inside match statements causes compilation error
body: <p>Is there some restriction on using let! inside match statements? I'm not sure why this won't compile.</p>
  
  <pre><code>module Foo =
    let Bar =
      async {      
        let result =
          match 1 with
          | 1 -&gt;
            let! num = async.Return 12345 // Doesn't compile
            1
          | _ -&gt; 2
  
        return result
      }
  </code></pre>
  
  <p>Compilation fails with "This construct may only be used within computation expressions" </p>