From: "Eregon (Benoit Daloze) via ruby-core" <ruby-core@...>
Date: 2026-07-13T21:20:49+00:00
Subject: [ruby-core:126078] [Ruby Misc#22192] Clarify the scope of default visibility changed inside a block

Issue #22192 has been updated by Eregon (Benoit Daloze).


TruffleRuby also behaves like CRuby here.
My understanding is method visibility is some state that only exists in methods and not in blocks (same as `$~`, etc).

There should already be some ruby/spec for that.

----------------------------------------
Misc #22192: Clarify the scope of default visibility changed inside a block
https://bugs.ruby-lang.org/issues/22192#change-118079

* Author: shugo (Shugo Maeda)
* Status: Assigned
* Assignee: matz (Yukihiro Matsumoto)
----------------------------------------
`private` etc. called with no arguments inside a block changes the default visibility of the enclosing lexical scope, and the change survives the block:

```ruby
class C
  %i[foo bar].each do |name|
    private
    define_method(name) { }
  end
  def afterwards; end   # also private
end
C.private_method_defined?(:foo)        #=> true
C.private_method_defined?(:afterwards) #=> true
```

When multiple Procs share the same lexical scope, `private` in a Proc affects all Procs:

```ruby
class Host
  SET_PRIVATE = proc { private }
  DEFINE      = proc { def probe; end }
end
Host::SET_PRIVATE.call
Host::DEFINE.call
Host.private_method_defined?(:probe)   #=> true
```

Neither CRuby nor ruby/spec has corresponding tests. I assume this is intentional, but am I correct?
It seems that the visibility change is effective only within the block on JRuby, so I'd like to clarify this.




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