array.rb: `Array#uniq` to return always `Array`.
Even called for subclass of `Array`, according to new Ruby3.0 behavior.
Other methods of `Array` behave as Ruby3.0 from the first hand.
@@ -51,7 +51,7 @@ class Array
# b.uniq { |s| s.first } # => [["student", "sam"], ["teacher", "matz"]]
#
def uniq(&block)
- ary = self.dup
+ ary = self[0..-1]
ary.uniq!(&block)
ary
end
