From: sawadatsuyoshi@...
Date: 2015-12-22T10:59:21+00:00
Subject: [ruby-core:72431] [Ruby trunk - Bug #11860] Double splat does not work on empty hash assigned via variable

Issue #11860 has been updated by Tsuyoshi Sawada.


I found more cases (other than via variable) that the double splat does not work on an empty hash. While parenthesis does not cause the issue:

    [**({})] # => []

expressions more complicated than that seem to cause the issue:

    [**({} if true)] # => [{}]
    [**(if true; {} end)] # => [{}]
    [**(false ? :foo : {})] # => [{}]


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Bug #11860: Double splat does not work on empty hash assigned via variable
https://bugs.ruby-lang.org/issues/11860#change-55725

* Author: Tsuyoshi Sawada
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: 2.3.0preview2 (2015-12-11 trunk 53028) [x86_64-linux]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
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When an empty hash is given as a literal, the double splat operates on it, and leaves nothing, which is expected.

    class String
      def foo; end
    end

    [**{}] # => []
    "foo".foo(**{}) # => nil
    "foo".send(**{}) # => nil

However, when an empty hash is given via variable, the double splat retains an empty hash in place.

    h = {}

    [**h] # => [{}]
    "foo".foo(**h) # => wrong number of arguments (given 1, expected 0)
    "foo".send(**h) # => wrong number of arguments (given 1, expected 0)



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