As I said elsewhere, the issue is D not having a good solution
for accepting both rvalues and lvalues by ref. Jonathan
mentioned auto ref, but it's not exactly implemented correctly.
In C++, it just takes all parameters as const T&, and that
works for both lvalues and rvalues.
The extra 200k copies are from the implementation taking all
parameters by value. If we didn't do that, sans a working auto
ref, things like tree.insert(element(5)) would fail to compile
(cannot pass an rvalue by reference)
-Steve
And Jonathan said also that 'auto ref' is not the solution for
non-template functions.
Probably 'auto ref' will never work for non-template functions.
So a general solution must be found first.
