0004623: Private constraints accepted by toplevel but not by compiler

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0004623

OCaml

OCaml general

public

2008-10-15 17:28

2010-04-27 09:16

Reporter

dario

Assigned To

garrigue

Priority

normal

Severity

minor

Reproducibility

always

Status

closed

Resolution

fixed

Platform

OS Version

Product Version

3.11+dev

Target Version

Fixed in Version

3.11+dev

Summary

0004623: Private constraints accepted by toplevel but not by compiler

Description

Using the just released 3.11 Beta1, the following code is accepted by the top-level:

module Foobar:
sig
        type foo_t = [ `A ]
        type bar_t = [ `B ]
        type foobar_t = [ foo_t | bar_t ]
        type 'a t = private 'a constraint 'a = [< foobar_t ]

        val make_a: unit -> foo_t t
        val make_b: unit -> bar_t t
end =
struct
        type foo_t = [ `A ]
        type bar_t = [ `B ]
        type foobar_t = [ foo_t | bar_t ]
        type 'a t = 'a constraint 'a = [< foobar_t ]

        let make_a () = `A
        let make_b () = `B
end

But is rejected by both the byte and native code compilers:

File "constraint.ml", line 1, characters 0-1:
Error: The implementation constraint.ml
       does not match the interface (inferred signature):
       Modules do not match:
         sig
           type foo_t = [ `A ]
           type bar_t = [ `B ]
           type foobar_t = [ `A | `B ]
           type 'a t = 'a Foobar.t constraint 'a = [< foobar_t ]
           val make_a : unit -> foo_t t
           val make_b : unit -> bar_t t
         end
       is not included in
         sig
           type foo_t = [ `A ]
           type bar_t = [ `B ]
           type foobar_t = [ `A | `B ]
           type 'a t = private 'a constraint 'a = [< foobar_t ]
           val make_a : unit -> foo_t t
           val make_b : unit -> bar_t t
         end
       Type declarations do not match:
         type 'a t = 'a Foobar.t constraint 'a = [< foobar_t ]
       is not included in
         type 'a t = private 'a constraint 'a = [< foobar_t ]

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related to

0004580

closed

garrigue

Stack overflow with private row type

Notes
(0004680) garrigue (manager) 2008-10-16 04:14	Actually the problem was not unrelated to constraints. A minimal reproduction case follows: module Foobar : sig type t = private int end = struct type t = int end This is now fixed in CVS/release311, by allowing head-expansion of private abbreviations when defining a private type.

(0005385) garrigue (manager) 2010-04-27 09:16	safe to close

Issue History
Date Modified	Username	Field	Change
2008-10-15 17:28	dario	New Issue
2008-10-16 04:14	garrigue	Status	new => resolved
2008-10-16 04:14	garrigue	Fixed in Version	=> 3.11+dev
2008-10-16 04:14	garrigue	Resolution	open => fixed
2008-10-16 04:14	garrigue	Assigned To	=> garrigue
2008-10-16 04:14	garrigue	Note Added: 0004680
2010-04-27 09:16	garrigue	Relationship added	related to 0004580
2010-04-27 09:16	garrigue	Note Added: 0005385
2010-04-27 09:16	garrigue	Status	resolved => closed