0004765: Structural equality should treat exception specifically - MantisBT

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ID

Project

Category

View Status

Date Submitted

Last Update

0004765

OCaml

OCaml general

public

2009-04-06 15:47

2012-08-02 08:58

Reporter

till

Assigned To

Priority

normal

Severity

feature

Reproducibility

always

Status

acknowledged

Resolution

open

Platform

OS

OS Version

Product Version

3.11.0

Target Version

4.01.0+dev

Fixed in Version

Summary

0004765: Structural equality should treat exception specifically

Description

let e = Not_found
let eq = function Not_found -> true | _ -> false
exception Not_found
let _ = e = Not_found (* True *)
let _ = eq Not_found (* False *)

Additional Information

IMHO The pattern matching behaviour seems to be the correct one. I guess the fix would be to change the equality function to handle exceptions specifically (i.e. do pointer equality on the first field).
This might require adding a new tag number for exceptions to be able to tell them apart at run time.

Tags

No tags attached.

Relationships

Notes
(0007864) xleroy (administrator) 2012-08-02 08:58	As the reporter says, significant changes in the representation of exceptions are required to address this issue: either reserve a new tag for by-address comparison, or use Object-tagged blocks for exceptions. Postponing to the next major release (optimistically).

Issue History
Date Modified	Username	Field	Change
2009-04-06 15:47	till	New Issue
2009-04-29 15:52	doligez	Status	new => acknowledged
2012-07-11 14:55	doligez	Target Version	=> 4.01.0+dev
2012-07-31 13:36	doligez	Target Version	4.01.0+dev => 4.00.1+dev
2012-08-02 08:58	xleroy	Note Added: 0007864
2012-08-02 08:58	xleroy	Severity	minor => feature
2012-08-02 08:58	xleroy	Target Version	4.00.1+dev => 4.01.0+dev

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