dup field in sub-class should be reported by the compiler

[Walter Bright]

Walter Bright wrote:
> Brad Roberts wrote:
>> On Mon, 13 Aug 2007, Walter Bright wrote:
>>> I just don't see the issue.
>>
>> Apply this same logic to variable shadowing.  Shadowing has been 
>> declared illegal.
> 
> While pedantically it is the same logic, but practically I think it's 
> very different. I don't see writing derived classes like one writes a 
> nested scope.

I want to add to that. For a nested scope, there really isn't any 
barrier to renaming something. For a derived class, however, you have 
users of it, and you may need to specifically hide a base member.