Bug #9291: array splatting a nil works, but hash splatting a nil does not

• Status: Rejected
• Priority: Normal
• Assignee: matz (Yukihiro Matsumoto)
• Target version: -
• ruby -v: ruby 2.0.0p353 (2013-11-22 revision 43784) [i686-linux]

[rits (First Last)]

irb(main):001:0> [nil]
=> []
irb(main):002:0> {*nil}
TypeError: no implicit conversion of nil into Hash

[rits (First Last)]

this could be used like this: method a: 1, **({b: 1} if condition)

[rits (First Last)]

So is there a reason * and ** should work differently for nil?

[marcandre (Marc-Andre Lafortune)]

• Assignee set to matz (Yukihiro Matsumoto)

Currently, * uses explicit conversion to array (to_a, not to_ary), while ** uses implicit conversion to hash (to_hash, not to_h).

So your question about nil can be explained this way, since nil.to_a #=> [] but nil.to_hash is not defined.

The real question is then: shouldn't ** be using explicit conversion to hash with to_h?

[mame (Yusuke Endoh)]

• Backport deleted (1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN)
• Status changed from Open to Rejected

Closing as it is by design. If you want the change, please open a feature request ticket with a use case.

[mame (Yusuke Endoh)]

• Is duplicate of Bug #8507: Keyword splat does not convert arg to Hash added