Feature #8449: Array#ary_plus always returns an array

• Status: Assigned
• Assignee: nobu (Nobuyoshi Nakada)
• Target version: -

[txemagon (José M. González)]

=begin

Even when Array is subclassified, + operator keeps on returning an Array.

Don't know if it is a bug or intentional, but it has surprised me for sure.

I paste some code for demonstrational purposes:

#!/usr/bin/env ruby
#ary_plus.rb

Shows an unexpected behavior to me

when adding Array subclasess.

class Subarray < Array; end

a = Subarray.new
b = Subarray.new

result = a + b

I was expecting to have a Subarray back

unless result.is_a? Subarray
puts "result is not a [Subarray]"
end

puts "result variable is a [#{result.class.name}]"

=end

[zzak (zzak _)]

• Category set to core
• Assignee set to nobu (Nobuyoshi Nakada)

For what it's worth this happens with String too:

class Substring < String; end
=> nil
a = Substring.new
=> ""
b = Substring.new
=> ""
result = a + b
=> ""
result.class
=> String

Maybe nobu can tell us

[hsbt (Hiroshi SHIBATA)]

• Status changed from Open to Assigned