title: Inconsistent assumptions over interface (Ocaml)
body: <p>I suddenly started to get this error. I don't know how to diagnose or fix it. Am I supposed to grep through <code>bar.ml</code> and check every Big_int function against signature in <code>Big_int.mli</code>?</p>
  
  <pre><code>File "foo.ml", line 1, characters 0-1:
  Error: The files /home/bar.cmi
         and /usr/lib/ocaml/big_int.cmi make inconsistent assumptions
         over interface Big_int
  </code></pre>