class Prism::ArrayPatternNode

def ===(other)

comparing the value of locations. Locations are checked only for presence.
Implements case-equality for the node. This is effectively == but without 
def ===(other)
  other.is_a?(ArrayPatternNode) &&
    (constant === other.constant) &&
    (requireds.length == other.requireds.length) &&
    requireds.zip(other.requireds).all? { |left, right| left === right } &&
    (rest === other.rest) &&
    (posts.length == other.posts.length) &&
    posts.zip(other.posts).all? { |left, right| left === right } &&
    (opening_loc.nil? == other.opening_loc.nil?) &&
    (closing_loc.nil? == other.closing_loc.nil?)
end