class RuboCop::Cop::Lint::UnreachableCode

This cop checks for unreachable code. The check are based on the presence of flow of control statement in non-final position in begin(implicit) blocks.

@example

# bad

def some_method
  return
  do_something
end

# bad

def some_method
  if cond
    return
  else
    return
  end
  do_something
end

@example

# good

def some_method
  do_something
end

Constants

MSG

Public Instance Methods

on_begin(node) click to toggle source
# File lib/rubocop/cop/lint/unreachable_code.rb, line 40
def on_begin(node)
  expressions = *node

  expressions.each_cons(2) do |expression1, expression2|
    next unless flow_expression?(expression1)

    add_offense(expression2)
  end
end
Also aliased as: on_kwbegin
on_kwbegin(node)
Alias for: on_begin

Private Instance Methods

check_case(node) click to toggle source
# File lib/rubocop/cop/lint/unreachable_code.rb, line 87
def check_case(node)
  else_branch = node.else_branch
  return false unless else_branch
  return false unless flow_expression?(else_branch)

  node.when_branches.all? do |branch|
    branch.body && flow_expression?(branch.body)
  end
end
check_if(node) click to toggle source
# File lib/rubocop/cop/lint/unreachable_code.rb, line 80
def check_if(node)
  if_branch = node.if_branch
  else_branch = node.else_branch
  if_branch && else_branch &&
    flow_expression?(if_branch) && flow_expression?(else_branch)
end
flow_expression?(node) click to toggle source
# File lib/rubocop/cop/lint/unreachable_code.rb, line 64
def flow_expression?(node)
  return true if flow_command?(node)

  case node.type
  when :begin, :kwbegin
    expressions = *node
    expressions.any? { |expr| flow_expression?(expr) }
  when :if
    check_if(node)
  when :case
    check_case(node)
  else
    false
  end
end