From: alxtskrnk@...
Date: 2015-12-09T05:40:14+00:00
Subject: [ruby-core:71981] [Ruby trunk - Bug #11779] Module#using does not make sense as a method

Issue #11779 has been updated by bug hit.


Shugo Maeda wrote:
> bug hit wrote:
> > Shugo Maeda wrote:
> > > bug hit wrote:
> > > > so if `using` inside module_eval is intended to work, then invoking such a module_eval from a method should also work (it raises Module#using is not permitted in methods):
> > > 
> > > Module#using is not intented to work as you expect.
> > > 
> > 
> > This wasn't really my expectation, it was nobu's explanation (It is not a noop, just you don't use the refined method there), which I confirmed.
> > 
> > "using" called from a module_eval block activates the refinement in the block
> > 
> > Are you saying that's a bug?
> 
> Nobu didn't explain that Module#using should work in methods.
> Module#using is designed not for such dynamic use.

Note that when #using is called in a module eval_block, it's effect is confined to the body of the block.  So why should it matter if module_eval is called from a method or top level or from another module/class?  Regardless of where it's called, #using inside it works the same.


----------------------------------------
Bug #11779: Module#using does not make sense as a method
https://bugs.ruby-lang.org/issues/11779#change-55389

* 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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