title: Where is the source code for the sequence expression builder
body: <p>I'm curious how the F# Seq computational expression implements the IEnumerable data structure.</p>
  
  <p>Searching <a href="https://github.com/fsharp/fsharp/blob/master/src/fsharp/FSharp.Core/seq.fs" rel="nofollow">Sharp.Core/seq.fs</a> on GitHub for the implementation of yield! ( YieldFrom(expr) ) isn't successful.</p>