Issue #16430 has been updated by MikeVastola (Mike Vastola).

Backport deleted (2.5: UNKNOWN, 2.6: UNKNOWN)
ruby -v deleted (ruby 2.6.3p62 (2019-04-16 revision 67580) [x86_64-linux])
Tracker changed from Bug to Feature

mame (Yusuke Endoh) wrote:
> It is by design.  See "Scope" section of https://github.com/ruby/ruby/blob/master/doc/syntax/modules_and_classes.rdoc

Ok, I see that, but is this a good design? I would argue know and I'm changing this to a feature request (I would ask it be re-opened.)

For me, this is literally the first instance -- having worked heavily with Ruby for the past 7 or so years -- wherein I have encountered something in the language that I found to be completely unintuitive. 

Further, the documentation linked states "This style has the benefit of allowing the author to reduce the amount of indentation. Instead of 3 levels of indentation only one is necessary." this benefit is heavily attenuated if it is not possible to maintain the same scope as the more heavily indented syntax.

For the feature request, I would suggest either adding any parent namespaces to the nesting, or else (if there is concern about this being a breaking change) add a variant for the scope resolution operator in declaring a class/module to alter how nesting is interpreted (maybe `A:::B` -- a triple colon)?

Lastly, I would argue that there are far fewer (if any) use cases for the current design than for what I am suggesting.

----------------------------------------
Feature #16430: Resultion of constants in enclosing class/module affected by how nested classes/modules are declared
https://bugs.ruby-lang.org/issues/16430#change-83301

* Author: MikeVastola (Mike Vastola)
* Status: Rejected
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
I'm not sure if this is intentional (in which case it really isn't documented anywhere, and probably should be) or a bug, but imagine the following code:

``` ruby
# lib/a.rb
module A
  FOO = :BAR
end

# lib/a/b.rb
require_relative '../a'
module A::B
  def foo
    FOO
  end
end

# lib/a/c.rb
require_relative '../a'
module A
  module C
    def foo
      FOO
    end
  end
end

```

If I were to evaluate `A::B.foo`, I would trigger a `NoMethodError (undefined method 'foo' for A::B:Module)`.
However, if I were to evaluate `A::C.foo`, I would get `:BAR`.

This was really confusing to debug because I've been writing the more compact syntax forever where possible without realizing it impacted variable resolution, and it seems kind of bizarre and counter-intuitive that it would work this way.


*  *  *  *

Also, playing with this a bit more, there are some really weird artifacts going on: apparently different methods within the same class/module can have different nestings depending on the context in which they were added to the class?

For example:
``` ruby
module A
  X = 1
end

module A::B
  X = 6
end

module A
  module B::C
    Y = 9
    Z = X + Y # 10
  end
end

module A::B
  module C
    N = X + Y # 15
  end
end

```




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