T[] find(T)(T[] haystack, T needle)
{
    while (haystack.length > 0 && haystack[0] != needle)
    {
        haystack = haystack[1 .. $];
    }
    return haystack;
}

unittest
{
    // Проверка способностей к обобщению
    double[] d = [ 1.5, 2.4 ];
    assert(find(d, 1.0) == null);
    assert(find(d, 1.5) == d);
    string[] s = [ "one", "two" ];
    assert(find(s, "two") == [ "two" ]);
}