From: "Eregon (Benoit Daloze)" <noreply@...>
Date: 2022-03-14T16:03:20+00:00
Subject: [ruby-core:107895] [Ruby master Bug#18632] Struct.new wrongly treats a positional Hash as keyword arguments

Issue #18632 has been updated by Eregon (Benoit Daloze).


And another maybe related issue, this time in Struct#new:
```
$ ruby -we 'p Struct.new(:name, :legs, keyword_init: true).new(name: "elefant", legs: 4)'  
#<struct name="elefant", legs=4>
^ OK

$ ruby -we 'p Struct.new(:name, :legs, keyword_init: true).new(4)'
-e:1:in `initialize': wrong number of arguments (given 1, expected 0) (ArgumentError)
	from -e:1:in `new'
	from -e:1:in `<main>'
^ fails as expected

$ ruby -we 'p Struct.new(:name, :legs, keyword_init: true).new({name: "elefant", legs: 4})'
#<struct name="elefant", legs=4>
^ should fail, it is not kwargs
```

And this example also show that providing `keyword_init: true` can cause an inconsistency:
```
I'm using master here to simplify:

$ ruby -we 'p Struct.new(:name, :legs, keyword_init: true).new({name: "elefant", legs: 4})'  
#<struct name="elefant", legs=4>
^ incorrect

$ ruby -we 'p Struct.new(:name, :legs).new({name: "elefant", legs: 4})'  
#<struct name={:name=>"elefant", :legs=>4}, legs=nil>
^ correct

$ ruby -we 'p Struct.new(:name, :legs).new(name: "elefant", legs: 4)'
#<struct name="elefant", legs=4>
^ correct
```

----------------------------------------
Bug #18632: Struct.new wrongly treats a positional Hash as keyword arguments
https://bugs.ruby-lang.org/issues/18632#change-96834

* Author: Eregon (Benoit Daloze)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [x86_64-linux]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
```
$ ruby -e 'Struct.new(:a, name: "b")'   
-e:1:in `new': unknown keyword: :name (ArgumentError)
	from -e:1:in `<main>'
^ expected

$ ruby -e 'Struct.new(:a, { name: "b" })'
-e:1:in `new': unknown keyword: :name (ArgumentError)
	from -e:1:in `<main>'
^ wrong
```

It shouldn't be such an error for the 2nd command since it's a positional Hash.
It should be a TypeError, like when passing e.g. `nil` instead of the positional Hash.

Also:
```
$ ruby -e 'p Struct.new(:a, {}).members'
[:a]
```
But it should be an error to pass a positional Hash.

I think this is worth fixing, because it basically breaks the separation of positional and keyword arguments for this method.
Also Struct.new does take a keyword argument, `keyword_init: true`.



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