Needle* find(Haystack, Needle)(return Haystack haystack, scope Needle needle) @safe
{
    size_t index = -1;
    foreach (i, ref val; haystack)
    {
        if (val == needle)
        {
            index = i;
        }
    }
    
    if (index != -1)
    	return &haystack[index]; //Error: returning &haystack[index] escapes a reference to parameter haystack, perhaps annotate with return
    else
    	return null;
}

void main() @safe
{
    int[9] haystack = [0, 10, 5, 6, 2, 3, 9, 4, 5];
    int* foundVal = haystack.find(3);
}