class Prism::IndexTargetNode

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?(IndexTargetNode) &&
    (flags === other.flags) &&
    (receiver === other.receiver) &&
    (opening_loc.nil? == other.opening_loc.nil?) &&
    (arguments === other.arguments) &&
    (closing_loc.nil? == other.closing_loc.nil?) &&
    (block === other.block)
end