[ruby-core:92222] [Ruby trunk Bug#15708] Implicit numbered argument decomposes an array

Issue #15708 has been updated by Eregon (Benoit Daloze).


For some reason, a reply on the tracker seems to have been lost, or removed.
I think it is highly relevant, so I'll quote it here:

sholden (Scott Holden) wrote:
> This is definitely not the behavior I would expect. In everything that I've seen, developers are describing the feature such that 
> 
> ``` ruby
> a.map{|x| x} == a.map{ @1 }
> ```
> 
> This would be a very surprising behavior for people to stumble upon.


----------------------------------------
Bug #15708: Implicit numbered argument decomposes an array
https://bugs.ruby-lang.org/issues/15708#change-77559

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.7.0dev
* Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN
----------------------------------------
In the following, `@1` refers to the entire item iterated:

```ruby
a = [1, 2, 3]
a.map{|x| x} # => [1, 2, 3]
a.map{@1} # => [1, 2, 3]
```

whereas in the following, `@1` refers to the first item achieved by decomposing the item iterated, behaving the same as `x` given by `|(x)|` rather than by `|x|`:

```ruby
a = [[1], [2], [3]]
a.map{|x| x} # => [[1], [2], [3]]
a.map{|(x)| x} # => [1, 2, 3]
a.map{@1} # => [1, 2, 3]
```

Is this intended?



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