From: alxtskrnk@...
Date: 2016-10-24T15:57:51+00:00
Subject: [ruby-core:77747] [Ruby trunk Bug#12861] super in a block can be either lexically or dynamically scoped depending on how the block is invoked

Issue #12861 has been updated by bug hit.


bug hit wrote:
> it would have to fail the same way instance_eval of the block (with super) fails when self is wrong (self has wrong type to call super in this context).

to expand on that, super normally binds to the method (class + method) lexically, so when it gets a self that's not compatible with its method binding it raises.

```ruby
class Class1
  def self.bar(&block)
	instance_eval(&block)
  end
end

class Class2
  def self.foo
    Class1.bar do
      super
    end
  end
end

Class2.foo #self has wrong type to call super in this context: Class (expected #<Class:Class2>)
```

This makes sense.  But in a define_method scenario (are there others?), the same super keyword suddenly starts binding to the method dynamically.  Such overloading of core characteristics of a given construct seems wrong.

----------------------------------------
Bug #12861: super in a block can be either lexically or dynamically scoped depending on how the block is invoked
https://bugs.ruby-lang.org/issues/12861#change-61050

* Author: bug hit
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-linux]
* Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN
----------------------------------------
```ruby
class Class1
  def self.foo
    'foo'
  end
  def self.method1
    'method1'
  end
end

class Class2 < Class1
  def self.foo
    bar do
      super()
    end
  end
  def self.bar(&block)
    a = block.()
    define_singleton_method :method1, &block
    b = send(:method1)
    c = block.()
    [a, b, c]
  end
end

p Class2.foo # ["foo", "method1", "foo"]
```

It doesn't seem like a good idea for a given language construct to be either lexically or dynamically scoped, depending on how its surrounding block is invoked (which is not visible at the point of definition).  I think it would be better if super were always lexically scoped, and a different keyword (dynamic_super) were always dynamically scoped



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

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