Make == for associative arrays test for equality, not identity. _aaEq was added to runtime/internal/aaA.d which forwards to TypeInfo_AssociativeArray.equals in genobj.d. On the codegen side, DtoAAEquals was added to gen/aa.cpp and is called from EqualExp::toElem in gen/toir.cpp. I assume that the frontend will produce an error if == is used on associative arrays of different type. This fixes DMD bug 1429.

// simple test of recursive types.
module llvmsample2;

import llvm.llvm;

void main()
{
    auto th = new TypeHandle();
    auto s = StructType.Get([ PointerType.Get(th.resolve) ], false);
    th.refine(s);
    s.dump();
    th.dispose();

    auto t = getTypeOf(s.ll);
    t.dump();

    assert(s is t);
}