Object.factroy successfully creates an invalid instance when used for an abstract class. There is no way to distinguish that the instance is invalid, as it is not null. It may be assigned, but upon first access it will result in a segfault. This also means that (AFAIK), short of looking at the vtbl, you have no way of knowing if a class is abstract using Typeinfo. Object.factory is supposed to return null when errors occur. Tested on Windows 7 64-bit (compiled as 32-bit) and Linux 64-bit.

Example:

import std.stdio;
import std.traits;
import std.conv;

abstract class C {
        string AbstractMethod();
}

C[] Objects;

void main() {
        TypeInfo_Class ti = typeid(C);
        C MyC = cast(C)Object.factory(ti.name);
        writefln("Created " ~ ti.name ~ " - IsNull: " ~ to!string(MyC is null) ~ " -  Location: " ~ to!string(&MyC) ~ ".");
        Objects ~= MyC;
        writefln("Added to collection.");
        writefln(Objects[0].AbstractMethod());
}


Output:

Created temptest.C - IsNull: false -  Location: 7FFF15772900.
Added to collection.
Segmentation fault