From: Jacques Garrigue <garrigue@math.nagoya-u.ac.jp>

> This is now fixed. I just hope this does not break anything...
> It should be ok, but please report any new non-termination problem
> immediately :-)

OK, my first solution was not correct, and caused infinite loops with

  type t = <a:u; b:int> and u = private t
  let f x = (x : t :> <a:'a; b:int> as 'a)

This is now fixed by distinguishing public and private expansions in
the expansion cache. This time I see no side-effect.

Jacques Garrigue