Issue #17279 has been updated by zverok (Victor Shepelev). FWIW, my PR with adjusting `Range#step` behavior fixes this, too: https://github.com/ruby/ruby/pull/7444 (as part of the unificatioin/simplification process): From the PR description:

Consistent support for negative step:

```ruby p (1..-10).step(-3).to_a #=> [1, -2, -5, -8] -- ArithmeticSequence backward iteration, on Ruby 3.3 and my code (1..-10).step(-3) { p _1 } # Ruby 3.3: step can't be negative (ArgumentError) -- inconsistent with ArithmeticSequence behavior # my code: prints 1, -2, -5, -8, consistent with ArithmeticSequence ``` ---------------------------------------- Feature #17279: Allow a negative step in Range#step with a block https://bugs.ruby-lang.org/issues/17279#change-109117 * Author: mrkn (Kenta Murata) * Status: Assigned * Assignee: matz (Yukihiro Matsumoto) ---------------------------------------- `Range#step` prohibits a negative step when a block is given. ```

...

(6..3).step(-1) {|i| p i } Traceback (most recent call last): 5: from /home/mrkn/.rbenv/versions/2.7/bin/irb:23:in `<main>' 4: from /home/mrkn/.rbenv/versions/2.7/bin/irb:23:in `load' 3: from /home/mrkn/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/irb-1.2.4/exe/irb:11:in `<top (required)>' 2: from (irb):1 1: from (irb):1:in `step' ArgumentError (step can't be negative)

But `Range#step` allows a negative step when it is called without a block.  In this case, `Range#step` creates an ArithmeticSequence, and `ArithmeticSequence#each` can iterate with a negative step.

...

(6..3).step(-1).each {|i| p i } 6 5 4 3 => ((6..3).step(-1))

I think the prohibition of a negative step in `Range#step` has already been meaningless, so it may be better to permit it for consistency.



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