[nem-bug] [Nemerle 0000638]: Co/contravariance for generic interfaces / delegates

[feedback at nemerle.org]

The following issue has been SUBMITTED.
======================================================================
<https://nemerle.org/bugs/view.php?id=638> 
======================================================================
Reported By:                steffen
Assigned To:                
======================================================================
Project:                    Nemerle
Issue ID:                   638
Category:                   Compiler
Reproducibility:            always
Severity:                   feature
Priority:                   normal
Status:                     new
======================================================================
Date Submitted:             03-25-2006 19:55 CET
Last Modified:              03-25-2006 19:55 CET
======================================================================
Summary:                    Co/contravariance for generic interfaces / delegates
Description: 
It would be nice to have co/contravariance support for generic parameters
of interfaces and delegates.

I.e. you should be able to do something like this:

interface IEnumerator[[covariant] T] {
  Current : T { get; }
  MoveNext() : bool;
}

interface IComparer[[contravariant] T] {
  Compare(x : T, y : T);
}

delegate EventHandler[[contravariant] T](arg : T) : void;

(The examples are from the CLI Spec II 9.5)

Btw.: It seems tha ncc doesn't support attribute for type parameter, e.g.

public class attr : System.Attribute { }

public interface X[[attr] 'a] { }

fails to compile.
======================================================================

Issue History
Date Modified  Username       Field                    Change              
======================================================================
03-25-06 19:55 steffen        New Issue                                    
======================================================================