Unnecessary warning when differentiating a function that mutates its array arg

[ZeptoStarling]

double example(double x, double *y)
{
    y[0] = 3;
    return x * y[0];
}

int main()
{
    double x = 10.0;
    double y[3] = {7.0, 4.6, 6.3};
    auto ex = clad::differentiate(example, "x");
    ex.dump();
    std::cout << ex.execute(x, y) << std::endl;
}

on Clad version 1.8~dev this gives a compilation warning:

warning: derivative of an assignment attempts to assign to unassignable expr, assignment ignored
    y[0] = 3;
           ^
1 warning generated.

This warning is a little confusing and could be interpreted as the code not working as intended, when in reality it produces expected results.