Re: [sv-ec] mantis item 2848

From: Gordon Vreugdenhil <gordonv_at_.....>
Date: Thu Aug 13 2009 - 15:30:49 PDT
Francoise,

This is where the "type" nature of interfaces really
breaks down.  I agree with the issue -- there is no
definite type for "vi.ch" since the referenced type
is dependent on the instance of the target.  Most
such issues were resolved by the introduction of
parameterized virtual interface typing, but strong
types (classes, unions, enums, structs) are not
addressed by the current LRM.  The "best" argument that
I can make is that since the types are not statically
determinable, it should probably be an error.  It
is certainly going to be ill-defined across vendors
at this point.

Gord.


Francoise Martinolle wrote:
> I filed a mantis item today regarding virtual interfaces which can get 
> assigned interfaces containing class declarations.
> I think it should be illegal to traverse through such virtual interface 
> to a class handle declared in the interface if its
> class datatype is also in the interface declaration.
> The datatype of the virtual interface select expression cannot be 
> statically determined by the elaborator.
> ex:
> interface ifc;
>    class C;
>    int i;
>    endclass
>      C ch;
>    
> endinterface // ifc
> 
> module top;
> 
>    ifc ifc1();
> 
>    ifc ifc2();
>    
>    virtual interface ifc vi = ifc1;
>    
>    initial begin
>       vi.ch = new(); // is this legal
>       $display(vi.ch.i); // is this legal?
>       vi = ifc2;
>       $display (vi.ch.i);
>    end
> 
> endmodule // top
>  
> Comments?
>  
> Francoise
>        '
> 
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Gordon Vreugdenhil                                503-685-0808
Model Technology (Mentor Graphics)                gordonv@model.com


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Received on Thu Aug 13 15:31:31 2009

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