Re: Dispatch on the result still does not work?

[Chris Moore <zmower@ntlworld.com>]

Dmitry A. Kazakov wrote:
> On Sat, 11 Jul 2009 12:09:57 +0100, Chris Moore wrote:
> 
>> Dmitry A. Kazakov wrote:
>>> Considering this one:
>>>
>>> package P is
>>>    type T is tagged null record;
>>>    function Value return T;
>>>       
>>>    type S is new T with null record;
>>>    function Value return S;
>>> end P;
>>>       
>>> package body P is
>>>    function Value return T is
>>>    begin
>>>       return (null record);
>>>    end Value;
>>>       
>>>    function Value return S is
>>>    begin
>>>       return (T with null record);
>>>    end Value;
>>> end P;
>>>
>>> use P;
>>>    
>>>    X : T'Class := S'(Value);
>>> begin
>>>    X := Value; -- Ambiguous?
>>>
>>> I would expect it rather dispatching on the tag of X, i.e. selecting Value,
>>> which returns S.
>>>
>> But X is of type T'Class.  Or did you mean X := X.Value;?
> 
> No. I meant function Value that has no arguments.

Then both versions of Value are in scope and return types that can be
assigned to T'Class.  Sounds ambiguous to me.

X := S'(Value);?