[Mono-devel-list] Generics - Class Constraint

[Stephen Quattlebaum]

Trying to compile some C# code that uses generics on mono in Linux (gentoo).
I ran across the following problem (which is probably just unimplemented
functionality).

 

       public static T QueryInterface<T>(object val)

            where T : class

        {

            if (val == null)

                return null;

 

            // First, see if the given object can be directly cast

            // to the requested type.  This will be a common case,

            // especially when checking for standard behavior interface

            // implementations (like IXrcDataElement).

            T tval = val as T;

            if (tval != null)

                return tval;

 

            . more .

        }

 

The error:

 

Xircle.Core/src/Core/XrcConvert.cs(118) error CS0077: The as operator should
be used with a reference type only (T is a value type)

 

Line #118 is the line that reads "T tval = val as T".  Looks like gmcs isn't
honoring the 'class' constraint (where T:class).  I found this bug in
bugzilla, which seems related:

 

http://bugzilla.ximian.com/show_bug.cgi?id=75368

 

The question:  Is that bug the same problem?  If so, I'll try compiling from
SVN again (got strange errors last time I tried), since the bug is marked
resolved.  If not, is there an ETA on when GMCS will honor 'class'
constraints?

 

The gmcs I'm using is from the bitrock installer of mono 1.1.8.3.

 

 

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