Bug #9291

array splatting a nil works, but hash splatting a nil does not

Added by First Last almost 2 years ago. Updated over 1 year ago.

Assignee:Yukihiro Matsumoto
ruby -v:ruby 2.0.0p353 (2013-11-22 revision 43784) [i686-linux] Backport:1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN


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


#1 Updated by First Last almost 2 years ago

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

#2 Updated by First Last over 1 year ago

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

#3 Updated by Marc-Andre Lafortune over 1 year ago

  • Assignee set to 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?

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