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 vec3
{
    float x,y,z;

    float dot(ref vec3 v)
    {
        return x*v.x + y*v.y + z*v.z;
    }

    void print(char[] n)
    {
        printf("%.*s = vec3(%.4f, %.4f, %.4f)\n", n.length, n.ptr, x,y,z);
    }
}

int main()
{
    printf("Dot Product test\n");

    const f = 0.7071067811865474617;
    vec3 v = vec3(f,f,0);
    vec3 w = vec3(f,0,f);

    v.print("v");
    w.print("w");

    auto dp = v.dot(w);
    printf("v · w = %f\n", dp);
    assert(dp > 0.4999 && dp < 0.5001);

    printf("  SUCCESS\n");
    return 0;
}