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.

extern(C) int printf(char*, ...);

struct V2D(T)
{
    T x,y;

    T dot(ref V2D v)
    {
        return x*v.x + y*v.y;
    }

    V2D opAdd(ref V2D v)
    {
        return V2D(x+v.x, y+v.y);
    }
}

alias V2D!(float) V2Df;

void main()
{
    printf("V2D test\n");
    auto up = V2Df(0.0f, 1.0f);
    auto right = V2Df(1.0f, 0.0f);
    assert(up.dot(right) == 0.0f);
    auto upright = up + right;
    assert(upright.x == 1.0f && upright.y == 1.0f);
    auto copy = upright;
    copy.x++;
    assert(copy.x > upright.x);
    printf("  SUCCESS\n");
}