class RuboCop::Cop::Lint::ShadowingOuterLocalVariable

Checks for the use of local variable names from an outer scope in block arguments or block-local variables. This mirrors the warning given by `ruby -cw` prior to Ruby 2.6: “shadowing outer local variable - foo”.

NOTE: Shadowing of variables in block passed to `Ractor.new` is allowed because `Ractor` should not access outer variables. eg. following style is encouraged:

[source,ruby]
----
worker_id, pipe = env
Ractor.new(worker_id, pipe) do |worker_id, pipe|
end
----

@example

# bad

def some_method
  foo = 1

  2.times do |foo| # shadowing outer `foo`
    do_something(foo)
  end
end

@example

# good

def some_method
  foo = 1

  2.times do |bar|
    do_something(bar)
  end
end

Constants

MSG

Public Class Methods

joining_forces() click to toggle source
# File lib/rubocop/cop/lint/shadowing_outer_local_variable.rb, line 53
def self.joining_forces
  VariableForce
end

Public Instance Methods

before_declaring_variable(variable, variable_table) click to toggle source
# File lib/rubocop/cop/lint/shadowing_outer_local_variable.rb, line 57
def before_declaring_variable(variable, variable_table)
  return if variable.should_be_unused?
  return if ractor_block?(variable.scope.node)

  outer_local_variable = variable_table.find_variable(variable.name)
  return unless outer_local_variable
  return if same_conditions_node_different_branch?(variable, outer_local_variable)

  message = format(MSG, variable: variable.name)
  add_offense(variable.declaration_node, message: message)
end
find_conditional_node_from_ascendant(node) click to toggle source
# File lib/rubocop/cop/lint/shadowing_outer_local_variable.rb, line 92
def find_conditional_node_from_ascendant(node)
  return unless (parent = node.parent)
  return parent if parent.conditional?

  find_conditional_node_from_ascendant(parent)
end
same_conditions_node_different_branch?(variable, outer_local_variable) click to toggle source
# File lib/rubocop/cop/lint/shadowing_outer_local_variable.rb, line 69
def same_conditions_node_different_branch?(variable, outer_local_variable)
  variable_node = variable_node(variable)
  return false unless variable_node.conditional?

  outer_local_variable_node =
    find_conditional_node_from_ascendant(outer_local_variable.declaration_node)
  return true unless outer_local_variable_node

  outer_local_variable_node.conditional? &&
    (variable_node == outer_local_variable_node ||
      variable_node == outer_local_variable_node.else_branch)
end
variable_node(variable) click to toggle source
# File lib/rubocop/cop/lint/shadowing_outer_local_variable.rb, line 82
def variable_node(variable)
  parent_node = variable.scope.node.parent

  if parent_node.when_type?
    parent_node.parent
  else
    parent_node
  end
end