From: alxtskrnk@...
Date: 2015-12-04T23:14:45+00:00
Subject: [ruby-core:71838] [Ruby trunk - Bug #11771] unable to pass keyargs	to []=

Issue #11771 has been updated by bug hit.


Eric Wong wrote:
> Affects back to 2.0 (when keyword args were introduced),
>  so this doesn't seem to be an optimization bug introduced in 2.1/2.2
>  
>  I'm actually not sure about the specs and if there's some special case
>  for kwargs interacting with aref/aset...
>  

The problem here is that the []= syntax compiled into a method dispatch where positional value arg is passed last, after keyargs, something you can't even do in ruby.

you can simulate the bug with a plain method:

```ruby

def foo(key, val, option: nil)
end

foo(:key, 1, option: 1) # ok
foo(:key, {option: 1}, 1) # wrong number of arguments (3 for 2)

```
 


----------------------------------------
Bug #11771: unable to pass keyargs to []=
https://bugs.ruby-lang.org/issues/11771#change-55242

* Author: bug hit
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: 2.2.3
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
```ruby
module Foo
  def self.[]=(key, val, option: nil)

  end
end

Foo[:key] = 1 # ok


Foo[:key, option: 1] = 1 # wrong number of arguments (3 for 2)

```

if you declare the []= params using *

```ruby

module Bar
  def self.[]=(*args)
    p args
  end
end

Bar[:key, option: 1] = 1 # args: [:key, {:option=>1}, 1]

```

the args end up [:key, {:option=>1}, 1] which seems wrong since the keyargs hash is supposed to be last




-- 
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