module RuboCop::Cop::Lint::UnusedArgument

Common functionality for cops handling unused arguments.

Public Instance Methods

after_leaving_scope(scope, _variable_table) click to toggle source
# File lib/rubocop/cop/mixin/unused_argument.rb, line 15
def after_leaving_scope(scope, _variable_table)
  scope.variables.each_value do |variable|
    check_argument(variable)
  end
end
autocorrect(node) click to toggle source
# File lib/rubocop/cop/mixin/unused_argument.rb, line 30
def autocorrect(node)
  return if %i[kwarg kwoptarg].include?(node.type)

  if node.blockarg_type?
    lambda do |corrector|
      range = range_with_surrounding_space(node.source_range, :left)
      range = range_with_surrounding_comma(range, :left)
      corrector.remove(range)
    end
  else
    ->(corrector) { corrector.insert_before(node.loc.name, '_') }
  end
end
check_argument(variable) click to toggle source
# File lib/rubocop/cop/mixin/unused_argument.rb, line 21
def check_argument(variable)
  return if variable.should_be_unused?
  return if variable_used?(variable)

  message = message(variable)
  add_offense(variable.declaration_node, location: :name,
                                         message: message)
end
join_force?(force_class) click to toggle source
# File lib/rubocop/cop/mixin/unused_argument.rb, line 11
def join_force?(force_class)
  force_class == VariableForce
end

Private Instance Methods

find_assignment_without_variable_usage(variable) click to toggle source

Find the first variable assignment, which doesn't reference the variable at the rhs.

# File lib/rubocop/cop/mixin/unused_argument.rb, line 68
def find_assignment_without_variable_usage(variable)
  variable.assignments.find do |assignment|
    # It's impossible to decide whether a branch is executed, so
    # this case is ignored
    next if assignment.branch

    assignment_node = assignment.meta_assignment_node || assignment.node

    !uses_var?(assignment_node, assignment.variable.name)
  end
end
variable_used?(variable) click to toggle source
# File lib/rubocop/cop/mixin/unused_argument.rb, line 46
def variable_used?(variable)
  return false unless variable.referenced?

  assignment_without_usage =
    find_assignment_without_variable_usage(variable)

  # If variable is either not assigned or assigned with usages,
  # then it's really used
  return true unless assignment_without_usage

  assignment_without_usage_pos =
    assignment_without_usage.node.source_range.begin_pos

  reference_positions =
    variable.references.map { |var| var.node.source_range.begin_pos }

  # Was variable referenced before it was reassigned?
  reference_positions.any? { |pos| pos <= assignment_without_usage_pos }
end