From: Lyle Johnson <ljohnson@...>
Date: 2001-11-09T08:25:51+09:00
Subject: [ruby-talk:24708] Re: Strange behaviour of Array#[]

> a = [1,2,3]
>
> a[2]      # => 3
> a[3]      # => nil
> a[4]      # => nil
>
> So far everthing is ok.
>
> a[3, 1]   # => []
> a[4, 1]   # => nil
>
> Why does a[3,1] returns [] instead of nil?

On first glance this appears to be a bug in rb_ary_subseq() (defined in
array.c). The first executable line uses this test:

    if (beg > RARRAY(ary)->len) return Qnil;

but should probably use this instead:

    if (beg > RARRAY(ary)->len - 1) return Qnil;

Lyle