"Common type" of the ternary operator expressions

[Ellery Newcomer]

On 05/24/2010 06:36 PM, Ali Çehreli wrote:
> Ali Çehreli wrote:
>> "Conditional Expressions" on this page covers the ternary operator as
>> well:
>>
>> http://digitalmars.com/d/2.0/expression.html#ConditionalExpression
>>
>> It says "the second and third expressions are implicitly converted to
>> a common type which becomes the result type of the conditional
>> expression."
>>
>> How "common" should the "common type" be? Wouldn't you expect the
>> following ternary operator's result be I, instead of Object?
>>
>> interface I {}
>> class A : I {}
>
> My expectation is that the hierarchy of A should look like this:
>
> Object
> |
> I
> |
> A

interfaces are not objects, so crush your expectations.

Question: what should happen with

class A : I, J {}
class B : I, J {}

?