Issue #10856 has been updated by Yukihiro Matsumoto.


It's because ** tries to pass keyword hash (this caes empty) as an argument, so that old style

  def foo(h)
  end
  foo(**{})

to work. In anyway, passing keyword arguments to a method that does not take any keyword argument can cause exception.
If you have real-world use-case, let us know.

Matz.


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Bug #10856: Splat with empty keyword args gives unexpected results
https://bugs.ruby-lang.org/issues/10856#change-52444

* Author: Sean Griffin
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-darwin13]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
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When keyword args are passed to a method with splat, and there are no keyword args, an empty hash is sent. I would expect no argument to be given, same as splat with an empty array. For example:

    def foo
    end

    foo(**{})

This causes an argument error, as an empty hash is passed. I would expect the same behavior as

    def foo
    end

    foo(*[])



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