class RuboCop::Cop::Lint::LiteralInInterpolation

“result is 10”
# good
@example
“result is #{10}”
# bad
@example
This cop checks for interpolated literals.

def autocorrect(node) 

def autocorrect(node)
  return if node.dstr_type? # nested, fixed in next iteration
  value = autocorrected_value(node)
  ->(corrector) { corrector.replace(node.parent.source_range, value) }
end

def autocorrected_value(node) 

def autocorrected_value(node)
  case node.type
  when :str
    node.children.last
  when :sym
    autocorrected_value_for_symbol(node)
  else
    node.source.gsub('"', '\"')
  end
end

def autocorrected_value_for_symbol(node) 

def autocorrected_value_for_symbol(node)
  end_pos =
    node.loc.end ? node.loc.end.begin_pos : node.loc.expression.end_pos
  range_between(node.loc.begin.end_pos, end_pos).source
end

def on_dstr(node) 

def on_dstr(node)
  node.each_child_node(:begin) do |begin_node|
    final_node = begin_node.children.last
    next unless final_node
    next if special_keyword?(final_node)
    next unless prints_as_self?(final_node)
    add_offense(final_node, :expression)
  end
end

def prints_as_self?(node)

Does node print its own source when converted to a string? 
def prints_as_self?(node)
  node.basic_literal? ||
    (COMPOSITE.include?(node.type) &&
      node.children.all? { |child| prints_as_self?(child) })
end

def special_keyword?(node) 

def special_keyword?(node)
  # handle strings like __FILE__
  (node.str_type? && !node.loc.respond_to?(:begin)) ||
    node.source_range.is?('__LINE__')
end