At compile time

[bearophile]

D2 is now able to execute math functions (sin, cos, sqrt, etc) at compile time.

This little C++ program compiles correctly with G++:

// C++ code
#include <math.h>
#include <stdio.h>

struct V3 {
    double x, y, z;
    V3(const double a, const double b, const double c) : x(a), y(b), z(c) {}
    V3 operator*(const double d) const { return V3(x * d, y * d, z * d); }
    V3 norm() const { return *this * (1.0 / sqrt(magsqr())); }
    double dot(const V3 &v) const { return x * v.x+y * v.y + z * v.z; }
    double magsqr() const { return dot(*this); }
};

const V3 v(V3(-0.5, -0.65, 0.9).norm());

int main() {
    printf("%f %f %f\n", v.x, v.y, v.z);
    return 0;
}


But similar D2 program produces, with DMD v.2.031:
test.d(12): Error: non-constant expression (V3(1,2,3)).norm()

// D2 code
import std.math, std.c.stdio;

struct V3 {
    double x, y, z;
    V3 opMul(double d) { return V3(x * d, y * d, z * d); }
    V3 norm() { return this * (1.0 / sqrt(this.magsqr())); }
    double dot(ref V3 v) { return x * v.x+y * v.y + z * v.z; }
    double magsqr() { return dot(this); }
}

const V3 v = V3(1.0, 2.0, 3.0).norm();

int main() {
    printf("%f %f %f\n", v.x, v.y, v.z);
    return 0;
}

Do you know why?
Can the D2 compiler modified/improved to allow this?

Bye and thank you,
bearophile