0004709: Typing of recursive modules to permissive

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0004709

OCaml

OCaml general

public

2009-02-05 14:49

2012-08-06 18:25

Reporter

Julien Signoles

Assigned To

Priority

normal

Severity

minor

Reproducibility

always

Status

acknowledged

Resolution

open

Platform

x86

Linux Ubuntu

OS Version

Product Version

3.11.0

Target Version

4.01.0+dev

Fixed in Version

Summary

0004709: Typing of recursive modules to permissive

Description

Hello,

I guess that the following program should not be typable, but it is with ocaml 3.11.0 and 3.10.2. It was not typable with ocaml 3.10.0.

=====
module F(X:sig type t end) = struct type t = X.t end

module rec A : sig type t end = struct type t = int end
and B: sig type t = int end = F(A)
=====

It seems that the explicit signature of A (with t abstract) is not used for typing B. Instead, that the inferred signature of A (with t = int) which is used. Thus program abstraction is broken.

Whenever I give a wrong type to the signature of B (e.g. type t = float), the program does not typed. So type safety is not broken. Ouf :).

Additional Information

The given program does not compile with ocaml 3.10.0 (don't try for ocaml 3.10.1). The expected error message is given.

=====
Signature mismatch:
Modules do not match:
sig type t = A.t end
is not included in
sig type t = int end
Type declarations do not match: type t = A.t is not included in type t = int
=====

Tags

recmod

Attached Files

Relationships

related to

0004336

closed

xleroy

Recursive modules can be used to break type safety

Notes
(0004832) Julien Signoles (reporter) 2009-02-05 14:51	Seem to be related to the fix of bug 4336 (which was: "Recursive modules can be used to break type safety").

(0004872) xleroy (administrator) 2009-03-28 17:00	I'm unsure how to go about this issue. I'm afraid it will stay for a while :-(

(0007911) xleroy (administrator) 2012-08-06 18:24	I've been sleeping on these PR for too long, and still have no idea how to address them. Unassigning them from myself.

Issue History
Date Modified	Username	Field	Change
2009-02-05 14:49	Julien Signoles	New Issue
2009-02-05 14:51	Julien Signoles	Note Added: 0004832
2009-03-28 17:00	xleroy	Note Added: 0004872
2009-03-28 17:00	xleroy	Assigned To	=> xleroy
2009-03-28 17:00	xleroy	Status	new => assigned
2012-07-11 14:59	doligez	Target Version	=> 4.01.0+dev
2012-07-29 18:00	frisch	Relationship added	related to 0004336
2012-07-29 18:01	frisch	Tag Attached: recmod
2012-07-31 13:36	doligez	Target Version	4.01.0+dev => 4.00.1+dev
2012-08-06 18:22	xleroy	Target Version	4.00.1+dev => 4.01.0+dev
2012-08-06 18:24	xleroy	Note Added: 0007911
2012-08-06 18:25	xleroy	Assigned To	xleroy =>
2012-08-06 18:25	xleroy	Status	assigned => acknowledged