Types A!1 and A!1u not considered equal?

[Tobias Brandt]

On 21 October 2011 10:01, Jonathan M Davis <jmdavisProg at gmx.com> wrote:
> On Friday, October 21, 2011 11:57:50 Gor Gyolchanyan wrote:
>> That's because implicit casts in D are much more strict, then those in
>> C/C++. Such seemingly intuitive cats, e.g. from long to int are not
>> performed due to potential loss of data.
>> Casting from int to uint has the same effect of potential loss of data.
>
> In D, integral types implicitly convert to their unsigned counterparts and
> vice versa. D does not consider those conversions to be narrowing conversions
> which require a cast (though they _are_ narrowing conversions and do risk
> messing up the number if it's too large or too small).

Obviously, the conversion does happen implicitly, otherwise
'new A!1' wouldn't compile (A expects a uint as parameter).
But then, why are A!1 and A!1u different types?