dmd 1.046 and 2.031 releases - is() expression

[The Anh Tran]

Andrei Alexandrescu wrote:
> I agree there are ugly constructs in D, and is-expressions would near 
> the top of the list (particularly the absolutely awful is(T : T[])), but 
> you have no case (heh) with the switch statement.
> 
> 
> Andrei

Just a funny suggestion: could we change the is() expression to 
imperative style?

Now:
template Something(T, U, V) if ( is(T : T[]) && is(...) )
{
      alias T blah1;
      U blah2;
      class C {};
      struct S {};
}

In mirror universe:
template Something(T, U, V)
in
{
     static if ( T : T[] ) // static if here mean if (is (...))
     {
        // may do something with T, make alias, change type
        // or check another constraint.
     }
     else
     {
         pragma(msg, "T must be Klingon");
         static assert(false); // Or return false; ????
     }

     static if ( U == int )
     {
        V = float; // ?????
     }
     return true;
}
body
{
      alias T blah1;
      U blah2;
      class C {};
      struct S {};
}