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.

class C
{
    int c;
    long f(long l)
    {
        return l;
    }
}

class D : C
{
    int d;
    override long f(long l)
    {
        return l*2;
    }
}

void main()
{
    scope c = new C;
    assert(c.f(25L) == 25);
    scope d = new D;
    assert(d.f(25L) == 50);
    C cd = d;
    assert(cd.f(25L) == 50);
    assert(func(d,25L) == 50);
}

long func(C c, long l)
{
    return c.f(l);
}