I think that's because i is being unified with int64 type in the seek_in call. So the type of i will be int64, and input_value polymorphic type variable will be int64. The unused binding j is not taken account and thrown away, so the type system will not take into account + operator that will cause i to be int. Why the unused binding is being thrown away before type checker, I don't know, maybe somebody could explain possibly. So from this is obvious why the second statement fails to type check.
Cheers; Wojciech On Tue, Jul 5, 2011 at 2:59 PM, malc <[email protected]> wrote: > Perhaps someone could explain why following behaves the way it does: > > ~$ ocaml > Objective Caml version 3.11.2 > > # let f ic = let i = input_value ic in let j = i + 1 in LargeFile.seek_in > ic i;; > Warning Y: unused variable j. > val f : in_channel -> unit = <fun> > # let f ic = let i = input_value ic in let j = i + 1 in LargeFile.seek_in > ic j;; > Error: This expression has type int but an expression was expected of type > int64 > > -- > mailto:[email protected] > > -- > Caml-list mailing list. Subscription management and archives: > https://sympa-roc.inria.fr/wws/info/caml-list > Beginner's list: http://groups.yahoo.com/group/ocaml_beginners > Bug reports: http://caml.inria.fr/bin/caml-bugs > > -- Caml-list mailing list. Subscription management and archives: https://sympa-roc.inria.fr/wws/info/caml-list Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
