Issue #10023 has been reported by Alexey Babich.

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Bug #10023: Hash#merge fails duplicating objects
https://bugs.ruby-lang.org/issues/10023

* Author: Alexey Babich
* Status: Open
* Priority: Normal
* Assignee: 
* Category: core
* Target version: 
* ruby -v: 2.1.2
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN
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Here is an example in IRB (ruby 2.1.2):
>> A={b:{}}
=> {:b=>{}}
>> c=A.merge({c: {d: 'e'}})
=> {:b=>{}, :c=>{:d=>"e"}}
>> c[:b][:d] = "f"
=> "f"
>> A
=> {:b=>{:d=>"f"}}

Every key, value pair is expected to be duplicated during the merge? Please, investigate if this is a bug



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