Class: RuboCop::Cop::Lint::SelfAssignment

Inherits:
Base
  • Object
show all
Defined in:
lib/rubocop/cop/lint/self_assignment.rb

Overview

Checks for self-assignments.

Examples:

# bad
foo = foo
foo, bar = foo, bar
Foo = Foo
hash['foo'] = hash['foo']
obj.attr = obj.attr

# good
foo = bar
foo, bar = bar, foo
Foo = Bar
hash['foo'] = hash['bar']
obj.attr = obj.attr2

# good (method calls possibly can return different results)
hash[foo] = hash[foo]

Constant Summary collapse

MSG = 
'Self-assignment detected.'
ASSIGNMENT_TYPE_TO_RHS_TYPE = 
{
  lvasgn: :lvar,
  ivasgn: :ivar,
  cvasgn: :cvar,
  gvasgn: :gvar
}.freeze

Constants inherited from Base

Base::RESTRICT_ON_SEND

Instance Attribute Summary

Attributes inherited from Base

#config, #processed_source

Instance Method Summary collapse

Methods inherited from Base

#active_support_extensions_enabled?, #add_global_offense, #add_offense, #always_autocorrect?, autocorrect_incompatible_with, badge, #begin_investigation, #callbacks_needed, callbacks_needed, #config_to_allow_offenses, #config_to_allow_offenses=, #contextual_autocorrect?, #cop_config, cop_name, #cop_name, department, documentation_url, exclude_from_registry, #excluded_file?, #external_dependency_checksum, inherited, #initialize, #inspect, joining_forces, lint?, match?, #message, #offenses, #on_investigation_end, #on_new_investigation, #on_other_file, #parse, #parser_engine, #ready, #relevant_file?, requires_gem, #string_literals_frozen_by_default?, support_autocorrect?, support_multiple_source?, #target_rails_version, #target_ruby_version

Methods included from ExcludeLimit

#exclude_limit

Methods included from AutocorrectLogic

#autocorrect?, #autocorrect_enabled?, #autocorrect_requested?, #autocorrect_with_disable_uncorrectable?, #correctable?, #disable_uncorrectable?, #safe_autocorrect?

Methods included from IgnoredNode

#ignore_node, #ignored_node?, #part_of_ignored_node?

Methods included from Util

silence_warnings

Constructor Details

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

Instance Method Details

#on_casgn(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/self_assignment.rb', line 56

def on_casgn(node)
  return unless node.rhs&.const_type?

  add_offense(node) if node.namespace == node.rhs.namespace &&
                       node.short_name == node.rhs.short_name
end

#on_lvasgn(node) ⇒ Object Also known as: on_ivasgn, on_cvasgn, on_gvasgn 



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# File 'lib/rubocop/cop/lint/self_assignment.rb', line 45

def on_lvasgn(node)
  return unless node.rhs

  rhs_type = ASSIGNMENT_TYPE_TO_RHS_TYPE[node.type]

  add_offense(node) if node.rhs.type == rhs_type && node.rhs.source == node.lhs.to_s
end

#on_masgn(node) ⇒ Object 



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# File 'lib/rubocop/cop/lint/self_assignment.rb', line 63

def on_masgn(node)
  add_offense(node) if multiple_self_assignment?(node)
end

#on_or_asgn(node) ⇒ Object Also known as: on_and_asgn 



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# File 'lib/rubocop/cop/lint/self_assignment.rb', line 67

def on_or_asgn(node)
  add_offense(node) if rhs_matches_lhs?(node.rhs, node.lhs)
end

#on_send(node) ⇒ Object Also known as: on_csend 



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# File 'lib/rubocop/cop/lint/self_assignment.rb', line 36

def on_send(node)
  if node.method?(:[]=)
    handle_key_assignment(node) if node.arguments.size == 2
  elsif node.assignment_method?
    handle_attribute_assignment(node) if node.arguments.size == 1
  end
end