On 04/28/2011 06:06 AM, rixed@happyleptic.org wrote:
> Although "let rec f = f" is unsound and rejected as expected,
> why is "let rec f : unit -> unit = f" also rejected, since it seams
> trivially equivalent to "let rec f () : unit = f ()" (which is
> accepted) ?

Eta-conversion (transforming "let f = f into let f () = f ()") is
unsound in the general case. Indeed, take for example:

let f () = print_string "titi"; function () -> print_string "toto"

Is "let g = f ()" equivalent to "let g () = f () ()" ? No.

So, no eta-expansion is ever performed using only type information.

Fabrice