float foo(float v[2]) {
    return v[0] * v[1];
}

void bar(inout float x) {
    float y[2], z;
    y[0] = x;
    y[1] = x * 2;
    z = foo(y);
    x = z;
}

void main() {
    float x = 10;
    bar(x);
    sk_FragColor = half4(half(x));
}