double.init is real.nan, is it a bug?

[bsd]

Hi all,


I think this is a bug, but if not I'm very confused and would 
like some clarification.

When checking double values that could be nan or unassigned I 
have to check both double.init and double.nan. But double.init IS 
double.nan.

---
void main() {
     // passes but I believe it is checked during compile
     assert(double.init is double.nan);

     double val;
     std.stdio.writeln( to!string(val) ); // writes "nan" to 
console
     assert(val is double.init); // passes
     assert(val is double.nan); // << FAILS (unexpectedly for me 
anyway)
}
---

Why does assert(val is double.nan) fail? Given:

a) double.init is double.nan
b) val is double.init
c) to!string(val) sees val as a nan

I also found this confusing:
---
void main() {

     assert(double.init is double.nan); // passes expected

     assert(double.init is float.init); // passes, unexpected
     assert(double.init is real.init); // passes, unexpected

     assert(double.init is real.nan); // passes, unexpected
     assert(double.init is float.nan); // passes, unexpected

}
---
I don't think these should be passing...should they??

I'm on fedora 19, dmd 2.063.2 extracted from the ZIP

Thanks