class Prism::MultiWriteNode

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?(MultiWriteNode) &&
    (lefts.length == other.lefts.length) &&
    lefts.zip(other.lefts).all? { |left, right| left === right } &&
    (rest === other.rest) &&
    (rights.length == other.rights.length) &&
    rights.zip(other.rights).all? { |left, right| left === right } &&
    (lparen_loc.nil? == other.lparen_loc.nil?) &&
    (rparen_loc.nil? == other.rparen_loc.nil?) &&
    (operator_loc.nil? == other.operator_loc.nil?) &&
    (value === other.value)
end