Original bug ID: 459
Reporter: administrator
Status: closed
Resolution: fixed
Priority: normal
Severity: minor
Category: ~DO NOT USE (was: OCaml general)

Bug description

Full_Name: Virgile Prevosto
Version: 3.01+1 (2001-04-19)
OS: RedHat 6.2
Submission from: etna.lip6.fr (132.227.83.203)

ocamlc plante sur le fichier suivant, au moment de la definition de Try2_.obj:

class virtual[ 't ] setoid =
object(sobj:'self)
method different (x:'t) (y:'t)= not (sobj#equal x y )
method virtual element: 't
method virtual equal: ('t)->('t)->bool
end;;

class [ 't , 'a, 'spec_a ] foo2((a):('spec_a))=
object(sobj:'self)
constraint 'spec_a= ( 'a)#setoid
constraint 't = bool
inherit [ 't ]setoid
method equal= (=)
method element= false
method my_foo= 2
end;;

class [ 't , 'f, 'spec_f ] bla((f):('spec_f))=
object(sobj:'self)
constraint 'spec_f= 'self -> ('f, 't, 'self)#foo2
constraint 't = int
inherit [ 't ]setoid
method printb (a:'t)= string_of_int a
val mutable my_spec=None
method my_spec = match my_spec with
None -> failwith "not initialized"
| Some s -> s
method element= (sobj#my_spec)#my_foo
method equal= (=)
initializer
my_spec <- Some (f (sobj))
end;;

module Try2_ =
struct
type f_t = bool
type fspec = stype -> (bool,rep,stype) foo2
and rep = int
and stype = (rep, f_t,fspec)bla
let obj = (new bla(fun f ->new foo2(f)) :>stype)
end
;;

Le message obtenu ne facilite pas la recherche de l'erreur:
Uncaught exception: File "typing/ctype.ml", line 0, characters 71629-71641:
Assertion failed

A priori, le probleme se trouve dans la resolution des contraintes de types: si
on definit

class type [ 't , 'f, 'spec_f ,'argt_f,'f_a] blatype =
object ('self)
constraint 'spec_f= 'argt_f -> ('f, 'f_a, 'argt_f)foo2
constraint 'argt_f = 'f_a #setoid
constraint 't = int
inherit [ 't ]setoid

method printb: ('t)->string
method my_spec: (bool, 't, 'self)foo2
method element: 't
method equal: ('t)->('t)->bool
end

avec deux parametres de types supplementaires (qu'on retrouve aussi dans la
definition de bla), et que Try2_.stype prend la forme
(...)blatype, la compilation s'effectue sans probleme, et les objets crees ont
le type (et le comportement) attendu.