Class: RuboCop::Cop::Lint::UselessSetterCall

Inherits:
Cop
  • Object
show all
Defined in:
lib/rubocop/cop/lint/useless_setter_call.rb

Overview

This cop checks for setter call to local variable as the final expression of a function definition.

Examples:


# bad

def something
  x = Something.new
  x.attr = 5
end

# good

def something
  x = Something.new
  x.attr = 5
  x
end

Defined Under Namespace

Classes: MethodVariableTracker

Constant Summary collapse

MSG = 
'Useless setter call to local variable `%<variable>s`.'.freeze
ASSIGNMENT_TYPES = 
%i[lvasgn ivasgn cvasgn gvasgn].freeze

Constants included from Util

Util::ASGN_NODES, Util::CONDITIONAL_NODES, Util::EQUALS_ASGN_NODES, Util::LITERAL_REGEX, Util::LOGICAL_OPERATOR_NODES, Util::MODIFIER_NODES, Util::OPERATOR_METHODS, Util::SHORTHAND_ASGN_NODES

Instance Attribute Summary

Attributes inherited from Cop

#config, #corrections, #offenses, #processed_source

Instance Method Summary collapse

Methods inherited from Cop

#add_offense, all, autocorrect_incompatible_with, badge, #config_to_allow_offenses, #config_to_allow_offenses=, #cop_config, cop_name, #cop_name, #correct, department, #duplicate_location?, #excluded_file?, #find_location, #highlights, inherited, #initialize, #join_force?, lint?, match?, #message, #messages, non_rails, #parse, qualified_cop_name, #relevant_file?, #target_rails_version, #target_ruby_version

Methods included from AST::Sexp

#s

Methods included from NodePattern::Macros

#def_node_matcher, #def_node_search, #node_search, #node_search_all, #node_search_body, #node_search_first

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #support_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

begins_its_line?, comment_line?, double_quotes_required?, escape_string, first_part_of_call_chain, interpret_string_escapes, line_range, needs_escaping?, on_node, operator?, parentheses?, same_line?, to_string_literal, to_supported_styles, tokens

Methods included from PathUtil

absolute?, match_path?, pwd, relative_path, reset_pwd, smart_path

Constructor Details

This class inherits a constructor from RuboCop::Cop::Cop

Instance Method Details

#on_def(node) ⇒ Object Also known as: on_defs 



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# File 'lib/rubocop/cop/lint/useless_setter_call.rb', line 31

def on_def(node)
  return unless node.body

  last_expr = last_expression(node.body)
  return unless setter_call_to_local_variable?(last_expr)

  tracker = MethodVariableTracker.new(node.body)
  receiver, = *last_expr
  variable_name, = *receiver
  return unless tracker.contain_local_object?(variable_name)

  add_offense(
    receiver,
    location: :name,
    message: format(MSG, variable: receiver.loc.name.source)
  )
end