[Mono-bugs] [Bug 633277] New: GMCS fails with CS0425 when implementing a generic method from an interface (while same code works on MS.Net)

[bugzilla_noreply at novell.com]

https://bugzilla.novell.com/show_bug.cgi?id=633277

https://bugzilla.novell.com/show_bug.cgi?id=633277#c0


           Summary: GMCS fails with CS0425 when implementing a generic
                    method from an interface (while same code works on
                    MS.Net)
    Classification: Mono
           Product: Mono: Compilers
           Version: SVN
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: Normal
          Priority: P5 - None
         Component: C#
        AssignedTo: mono-bugs at lists.ximian.com
        ReportedBy: pruiz at netway.org
         QAContact: mono-bugs at lists.ximian.com
          Found By: ---
           Blocker: ---


Created an attachment (id=384526)
 --> (http://bugzilla.novell.com/attachment.cgi?id=384526)
Sample code demostrating the issue

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US)
AppleWebKit/533.4 (KHTML, like Gecko) Chrome/5.0.375.125 Safari/533.4


Having the following interface defined on project-a:

   using System;

   namespace DomainServices
   {
        public interface IServicesContainer
        {
                void Register<I, T>() where T : I;

                void Register<I>(object instance);
        }
   }

And this implementation on project-b:

   using System;
   using System.Collections.Generic;

   namespace DomainServices
   {

        public class DictionaryServicesContainer : IServicesContainer
        {
                public void Register<I, T>()
                        where T : I
                {
                        throw new NotImplementedException();
                }

                public void Register<I>(object instance)
                {
                        throw new NotImplementedException();
                }

                public I Resolve<I>()
                {
                        throw new NotImplementedException();
                }
        }

   }

GMCS will fail during project-b compilation due to CS0425. However the same
code works on ms compiler.

The exacto error is: 

/opt/mono-trunk/bin/gmcs /out:b.dll /t:library ServicesContainer.cs
-reference:a.dll
ServicesContainer.cs(9,21): error CS0425: The constraints for type parameter
`T' of method `DomainServices.DictionaryServicesContainer.Register<I,T>()' must
match the constraints for type parameter `T' of interface method
`DomainServices.IServicesContainer.Register<I,T>()'. Consider using an explicit
interface implementation instead
/tmp/a.dll (Location of the symbol related to previous error)
Compilation failed: 1 error(s), 0 warnings


I've attached sample code demostrating the issue.

Reproducible: Always

Steps to Reproduce:
1. gmcs /out:a.dll /t:library IServicesContainer.cs
2. gmcs /out:b.dll /t:library ServicesContainer.cs -reference:a.dll
3. See error from gmcs..
Actual Results:  
ServicesContainer.cs(9,21): error CS0425: The constraints for type parameter
`T' of method `DomainServices.DictionaryServicesContainer.Register<I,T>()' must
match the constraints for type parameter `T' of interface method
`DomainServices.IServicesContainer.Register<I,T>()'. Consider using an explicit
interface implementation instead
/tmp/a.dll (Location of the symbol related to previous error)
Compilation failed: 1 error(s), 0 warnings


Expected Results:  
code compiled w/o errors.

I've testes this on mono-2.6.7 and it works as expected.. So it seems like a
trunk-only issue. (maight be a regression?)

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