Issue #10259 has been updated by Nobuyoshi Nakada.

Duplicated by Bug #10299: alias_method :new_foo=, :"#{:foo}="  doesn't work properly on ruby 2.2.0preview1. added

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Bug #10259: send を使った attr_writer への書き込みができない場合がある
https://bugs.ruby-lang.org/issues/10259#change-49115

* Author: Fumiaki Matsushima
* Status: Closed
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: 2.2.0dev, 2.2.0-preview1
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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```
class Hoge; attr_writer :a; end

Hoge.new.send(:"#{:a}=", 1)
# => 1 (ruby 2.1.2)
# hoge.rb:3:in `<main>': undefined method `a=' (ruby 2.2.0-preview1)
```



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