[ruby-core:121958] [Ruby Bug#21319] Namespaces do not support including mixins

10 May 2025

      Issue #21319 has been updated by fxn (Xavier Noria).

Maybe the root cause is _enabling_ namespaces with `RUBY_NAMESPACE=1`.

----------------------------------------
Bug #21319: Namespaces do not support including mixins
https://bugs.ruby-lang.org/issues/21319#change-113072

* Author: fxn (Xavier Noria)
* Status: Open
* Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN
----------------------------------------
The following program

```ruby
module M
end

class C
  include M
end
```

fails under a namespace with error

```
'Module#include': Cannot include refinement (TypeError)
```

-- 
https://bugs.ruby-lang.org/