From: "Eregon (Benoit Daloze) via ruby-core" <ruby-core@...>
Date: 2022-12-29T20:10:11+00:00
Subject: [ruby-core:111511] [Ruby master Bug#19278] Constructing subclasses of Data with positional arguments

Issue #19278 has been updated by Eregon (Benoit Daloze).


It seems hard to solve to me, without losing the significant advantages that @zverok mentions.

Also inheriting from a Data class seems kind of an anti/rare pattern.
One can of course:
```ruby
Foo = Data.define(:x, :y)
  def custom
  end
  ...
end
```

----------------------------------------
Bug #19278: Constructing subclasses of Data with positional arguments
https://bugs.ruby-lang.org/issues/19278#change-100881

* Author: tenderlovemaking (Aaron Patterson)
* Status: Feedback
* Priority: Normal
* ruby -v: ruby 3.2.0 (2022-12-25 revision a528908271) [arm64-darwin22]
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN
----------------------------------------
I'd expect both of the following subclasses to work, but the subclass that uses positional parameters raises an exception:

```ruby
Foo = Data.define

class Bar < Foo
  def initialize foo:
    p foo
  end
end

class Baz < Foo
  def initialize foo
    p foo
  end
end

Bar.new foo: 1 # Prints 1
Baz.new 1    # Raises ArgumentError
```

I'd expect the subclass that uses positional arguments to work.



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