From: alxtskrnk@...
Date: 2015-12-07T17:43:29+00:00
Subject: [ruby-core:71918] [Ruby trunk - Bug #11779] Module#using does not make sense as a method

Issue #11779 has been updated by bug hit.


Yukihiro Matsumoto wrote:
> Providing a feature by a method does not imply dynamic scoping, for example, Module#private etc. work in lexical scope.
> 
> Matz.

actually `private` is more dynamic than `using`, here's an example of private working not on the currently open class but on the dynamically bound default definee:

```ruby
Class1.class_eval do

  private

  def meth1

  end

end


Class1.new.meth1 # private method `meth1' called
```

whereas using is not affected by `self` or "default definee"

```ruby
module Refinement
  refine String do
    def refined?
      true
    end
  end
end

module Foo
  #using Refinement
  def self.refined?
    ''.refined? rescue false
  end
end

Foo.module_eval do
  using Refinement 
  p refined? # false
end

p Foo.refined? #false
```

Is the above behavior correct?  Instead of doing nothing, should this use of `using` produce an error or perhaps work inside the `module_eval` block 



----------------------------------------
Bug #11779: Module#using does not make sense as a method
https://bugs.ruby-lang.org/issues/11779#change-55324

* Author: bug hit
* Status: Feedback
* Priority: Normal
* Assignee: 
* ruby -v: 2.2.3
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
1. it can't be called from another method
2. the receiver must be self
3. since refinements are lexically scoped the self receiver must match the currently open class

#3 is particularly curious

```ruby
module Refinement
  refine String do
    def refined?
      true
    end
  end
end

module Foo
  def self.refined?
    ''.refined? rescue false
  end
end


module Bar
  def self.refined?
    ''.refined? rescue false
  end
  Foo.module_eval do
    using Refinement

  end
end

p Foo.refined? #false
```

The module_eval `#using` call does not raise (it's not from a method and the receiver is self), but evidently because currently open class does not match self, it does not do anything. So it should at least raise.

So `#using`, though a method, does not function as a method, which is misleading.



-- 
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