class RuboCop::Cop::Lint::Void

end
do_something(some_array)
some_array.sort!
def some_method(some_array)
end
some_var
do_something
def some_method(some_var)
end
some_num * 10
do_something
def some_method
# good
end
do_something(some_array)
some_array.sort
def some_method(some_array)
# bad
@example CheckForMethodsWithNoSideEffects: true
end
do_something
some_var
def some_method(some_var)
end
do_something
some_num * 10
def some_method
# bad
@example CheckForMethodsWithNoSideEffects: false (default)
methods used in void context.
This cop checks for operators, variables, literals, and nonmutating

def check_begin(node) 

def check_begin(node)
  expressions = *node
  expressions.pop unless in_void_context?(node)
  expressions.each do |expr|
    check_expression(expr)
  end
end

def check_defined(node) 

def check_defined(node)
  return unless node.defined_type?
  add_offense(node, message: format(DEFINED_MSG, defined: node.source))
end

def check_expression(expr) 

def check_expression(expr)
  check_void_op(expr)
  check_literal(expr)
  check_var(expr)
  check_self(expr)
  check_defined(expr)
  return unless cop_config['CheckForMethodsWithNoSideEffects']
  check_nonmutating(expr)
end

def check_literal(node) 

def check_literal(node)
  return if !node.literal? || node.xstr_type?
  add_offense(node, message: format(LIT_MSG, lit: node.source))
end

def check_nonmutating(node) 

def check_nonmutating(node)
  unless node.send_type? &&
         NONMUTATING_METHODS.include?(node.method_name)
    return
  end
  add_offense(node, message: format(NONMUTATING_MSG,
                                    method: node.method_name))
end

def check_self(node) 

def check_self(node)
  return unless node.self_type?
  add_offense(node, message: SELF_MSG)
end

def check_var(node) 

def check_var(node)
  return unless node.variable? || node.const_type?
  add_offense(node,
              location: :name,
              message: format(VAR_MSG, var: node.loc.name.source))
end

def check_void_op(node) 

def check_void_op(node)
  return unless node.send_type? && OPERATORS.include?(node.method_name)
  add_offense(node,
              location: :selector,
              message: format(OP_MSG, op: node.method_name))
end

def in_void_context?(node) 

def in_void_context?(node)
  parent = node.parent
  return false unless parent && parent.children.last == node
  VOID_CONTEXT_TYPES.include?(parent.type) && parent.void_context?
end

def on_begin(node) 

def on_begin(node)
  check_begin(node)
end

def on_block(node) 

def on_block(node)
  return unless node.body && !node.body.begin_type?
  return unless in_void_context?(node.body)
  check_expression(node.body)
end