Issue #9701 has been reported by Tsuyoshi Sawada.

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Bug #9701: RDoc description for `String#<<` and `String#concat`
https://bugs.ruby-lang.org/issues/9701

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
* ruby -v: 2.1.0p0
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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As far as I can see, `String#<<` is an alias of `String#concat`, but in the RDoc, there is no mentioning of the connection between them. `String#<<` should be simply described as an alias of `String#concat`.



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