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Feature #16456

Updated by aaronc81 (Aaron Christiansen) 11 months ago

A method defined with `...` as its parameter list is equivalent to one defined with `*args, &blk`, according to `Method#parameters`. 

 ```ruby 
 def foo(...); end 
 p method(:foo).parameters 
 # => [[:rest, :*], [:block, :&]] 
 ``` 

 Even in Ruby 2.7, `...` and `*args, &blk` are not *quite* _quite_ equivalent as the latter may produce a warning where the former does not. In Ruby 3.0 and beyond, `...` and `*args, &blk` will have a substantial semantic difference. Due to this, I don't consider the current behaviour of `Method#parameters` particularly ideal when dealing with methods using this new syntax. 

 If the goal of `...` is to be a "delegate everything" operator, even when parameter passing is changed like in Ruby 3.0, I would propose that `Method#parameters` considers it a unique type of parameter. For example: 

 ```ruby 
 def foo(...); end 
 p method(:foo).parameters 
 # => [[:delegate, :"..."]] 
 ```

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