class RuboCop::AST::NodePattern::Compiler::Binding

def bind(name)
  var = @bound.fetch(name) do
    yield n = @bound[name] = "unify_#{name.gsub('-', '__')}"
    n
  end
  if var == :forbidden_unification
    raise Invalid, "Wildcard #{name} was first seen in a subset of a " \
                   "union and can't be used outside that union"
  end
  var
end