0004478: Type error message when constructors are mis-ordered could be clearer

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0004478

OCaml

OCaml general

public

2008-01-13 17:43

2010-05-21 05:38

Reporter

dra

Assigned To

garrigue

Priority

normal

Severity

feature

Reproducibility

always

Status

closed

Resolution

fixed

Platform

OS Version

Product Version

3.09.3

Target Version

Fixed in Version

3.12.0+dev

Summary

0004478: Type error message when constructors are mis-ordered could be clearer

Description

Foo.ml:

type t = A | B

Foo.mli

type t = B | A

Running ocamlc -c t.mli t.ml correctly reports that...
The implementation t.ml does not match the interface t.cmi:
Type declarations do not match:
type t = B | A
is not included in
type t = A | B

However, the mismatch is only because the constructors are misordered. This is a slightly cryptic error unless you know about the internals of OCaml - perhaps in this instance, ocamlc could note that the types would be compatible if the constructors were in the same order?

Additional Information

I was being daft here and wrote an mli file with my brain switched off. Although I know from writing C stubs that the constructors must obviously be in the same order for the types to be the same, it took quite me some time to realise my stupidity because the type I was dealing with was much longer. The additional warning would be most useful!

I presume 3.10.1 behaves the same way...

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related to

0004819

closed

garrigue

Type error on record declarations too hard to read

Notes
(0005480) garrigue (manager) 2010-05-21 05:38	Error messages concerning type declaration mismatches have been greatly improved for 3.12.

Issue History
Date Modified	Username	Field	Change
2008-01-13 17:43	dra	New Issue
2008-01-18 15:37	doligez	Status	new => acknowledged
2010-04-30 07:25	garrigue	Status	acknowledged => assigned
2010-04-30 07:25	garrigue	Assigned To	=> garrigue
2010-05-21 05:38	garrigue	Note Added: 0005480
2010-05-21 05:38	garrigue	Status	assigned => closed
2010-05-21 05:38	garrigue	Resolution	open => fixed
2010-05-21 05:38	garrigue	Fixed in Version	=> 3.12.0+dev
2010-05-21 05:51	garrigue	Relationship added	related to 0004819