Issue #18268 has been updated by koic (Koichi ITO).


Thank you for the information source. This looks like a breaking change in Ruby 3.1, but it's okay if it's a considered impact.

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Bug #18268: Behavior change when `each_cons` and `break ... if false` are combined in Ruby 3.1
https://bugs.ruby-lang.org/issues/18268#change-94320

* Author: koic (Koichi ITO)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.1.0dev (2021-10-26T00:30:42Z master 7d4c59203f) [x86_64-darwin19]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
I'm not sure the details, but the following behavior has changed between Ruby 3.0.2 (and earlier) and Ruby 3.1.0-dev.

```ruby
# example.rb
def foo
  [1, 2].each_cons(2) do |one, two|
    break one if false
  end
end

p foo
```

## Expected Behavior (Ruby 3.0.2)

It returns `nil`.

```console
% rbenv local 3.0.2
% ruby -v
ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [x86_64-darwin19]
% ruby example.rb
nil
```

## Actual Behavior (Ruby 3.1.0-dev)

It returns `[1, 2]`.

```console
% rbenv local 3.1.0-dev
% ruby -v
ruby 3.1.0dev (2021-10-26T00:30:42Z master 7d4c59203f) [x86_64-darwin19]
% ruby example.rb
[1, 2]
```

I encountered this issue with the following RuboCop build error.
https://app.circleci.com/pipelines/github/rubocop/rubocop/5414/workflows/4a7e4b81-7380-41e5-8ede-e28d9160010d/jobs/201236

The code I encountered is below.
https://github.com/rubocop/rubocop/blob/v1.22.2/lib/rubocop/cop/layout/block_alignment.rb#L104-L106



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