StructType.init and StructType() cause a allocation

[Benjamin Thaut]

If T is a struct both of the following statements will lead to a call of 
the _d_arrayliteral function which will allocate a array of the size of 
the struct just to initialize it!!

void T[] data = ...;

data[0] = T.init;
data[0] = T();

This has proven to be the biggest performance bottleneck in my current 
codebase, replacing this statement with a unneccessary workaround speeds 
my code up by factor 100. This is the cause because all of my container 
classes tend to reinitialize the contents of the data arrays they are 
holding. Also this bug makes it very hard to write non leaking code when 
not using a GC. The replacement code could be

T temp;
data[0] = temp;

Which works correctly as long as T is publicly accessible, if it is a 
private type this will not compile. Then you have to do some more fancy 
stuff like:

void[T.sizeof] temp;
void[] initMem = typeid(T).init();
if(initMem.ptr is null)
   memset(temp.ptr, 0, temp.length);
else
   temp[] = initMem[];
data[0] = *cast(T*)temp.ptr;

How hard would it be to fix this?

It is really a shame that reinitalizing a struct
a) is a major performance bottleneck
b) leaks memory

I created a bug ticket for this 6 months ago, but it has been ignored so 
far: http://d.puremagic.com/issues/show_bug.cgi?id=7271

Kind Regards
Benjamin Thaut