class RuboCop::Cop::Lint::ShadowedArgument

def argument_references(argument)
  assignment_references = argument
                          .assignments
                          .flat_map(&:references)
                          .map(&:source_range)
  argument.references.reject do |ref|
    next false unless ref.explicit?
    assignment_references.include?(ref.node.source_range)
  end
end