Struct delegate access corruption

[z]

So i've upgraded one of my structs to use the more flexible 
delegates instead of function pointers but when the member 
function tries to access the struct's members, the contents are 
random and the program fails.

i've isolated the problem by adding writefln calls before calling 
the delegate and inside the delegate(the functions are defined in 
the struct as member functions, the delegate itself is set in the 
constructor) :

In the code that uses the delegate :
>writefln!"test %s"(a, &a);
>T b = a.d();//the delegate
While in the most used delegate :
>writefln!"test2 %s %s"(this, &this);
The contents and pointers don't match(they're random, full of 0, 
-nan, -inf and other invalid values), are they(delegates) 
supposed to be used like this?
Big thanks