Cannot Instantiate Immutable or Constant Structure Variable

[Loopback]

Hello!

Since I haven't received an answer for several days at the "learn"
newsgroup I was wondering if this was an error related to D or just
a hard nut to crack.

The unittest in this code is not compile-able, whereas the compiler
complains saying that the expression cannot be evaluated at compile
time (the constructor).

http://pastebin.com/CBJE24h1

I'm sorry if I seem impatient about creating a thread here, but my
development have come to a full halt because of this (seamlessly)
small problem.