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instance method

Set::SubclassCompatible#<

<(set)

lib/set/subclass_compatible.rb View on GitHub ↗

# File tmp/rubies/ruby-4.1.0-preview1/lib/set/subclass_compatible.rb, line 143
def proper_subset?(set)
  case
  when set.instance_of?(self.class)
    super
  when set.is_a?(Set)
    size < set.size && all?(set)
  else
    raise ArgumentError, "value must be a set"
  end
end

Alias of #proper_subset?

See also #proper_subset? #<= #- #+ also in 4.0

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