Issue #11213 has been reported by Koichi Sasada.

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Bug #11213: defined?(super) ignores respond_to_missing?
https://bugs.ruby-lang.org/issues/11213

* Author: Koichi Sasada
* Status: Open
* Priority: Normal
* Assignee: Yukihiro Matsumoto
* ruby -v: 2.3dev
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
```ruby
class C0
  def method_missing *args
    p [:method_missing] + args
  end
  def respond_to_missing? *args
    true
  end
end

class C1 < C0
  def foo
    super
    defined?(super)
  end
end

p C1.new.foo
```

This script prints

```
[:method_missing, :foo]
nil
```

In this case, we can call super, but defined? returns nil.
It should be a bug.




-- 
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