Direct access to struct construction, copying and destruction

[Benjamin Thaut]

While writing certain parts of my own little standard library 
(containers etc) I had to notice that D has a overcomplicated way of 
especially postblitting and destructing structs. By overcomplicated I 
mean that you don't have any other choice but to go through a TypeInfo 
object to the process correctly.

Postblitting:
If the struct has a postblit constructor you can directly call 
__postblit but if it does not have one, you have to go over the TypeInfo 
object to call __fieldPostBlit which is not directly exposed.

Destruction:
Pretty mutch the same situation as for postblitting. If it has a own 
destructor you can call __dtor, but if not you have to use the typeinfo 
object to call the destructor because the appropirate destructor is not 
directly exposed.

I find this strange because having to go through a TypeInfo object, 
which is a lot of unneccessary indirections for calling a function that 
is known at compile time and could even be inlined if it would be called 
directly, seems totaly overkill to me.

I would find it extremly usefull for low level code (unsafe of course) 
to have 3 simple functions that do the following:

cpctor: if present struct needs to be copy constructed, always calls the 
correct copy constructor

postblit: if present the struct needs to be postblit constructed, calls 
__postblit if the struct has a own postblit constructor, otherwise it 
calls __fieldPostBlit

dtor: if present the struct needs to be destructed. Calls the 
appropriate destructor.

This would give a better low level control over struct construction and 
destruction and would allow compilers to inline the functions if 
appropriate.

If some or all of the above is wrong, I'm going to look forward to 
beeing corrected.

Kind Regards
Benjamin Thaut