Are D classes always garbage collected?

[Froglegs]

>> You can allocate classes anywhere, if you're OK with 
>> forfeiting safety guarantees. For example, see emplace in 
>> std.conv:
>>
>> http://dlang.org/phobos/std_conv.html#emplace

Hum calling emplace ending up calling this bit of code..

T* emplace(T)(T* chunk)
    if (is(T == class))
{
    *chunk = null;
    return chunk;
}

Which returned me a nice fat null pointer.. wth? Perhaps that 
should be a compile time error if you aren't supposed to use 
classes..


I tried placement new syntax but this tells me I need an 
allocator, whatever that means..

I swear D is google proof sigh