Another shot at fixing the issues with (constant) struct literals and their addresses. See DMD2682, #218, #324. The idea is to separate the notion of const from 'this variable can always be replaced with its initializer' in the frontend. To do that, I introduced Declaration::isSameAsInitializer, which is overridden in VarDeclaration to return false for constants that have a struct literal initializer. So {{{ const S s = S(5); void foo() { auto ps = &s; } // is no longer replaced by void foo() { auto ps = &(S(5)); } }}} To make taking the address of a struct constant with a struct-initializer outside of function scope possible, I made sure that AddrExp::optimize doesn't try to run the argument's optimization with WANTinterpret - that'd again replace the constant with a struct literal temporary.

// 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);
}