class RuboCop::Cop::Lint::LiteralInInterpolation

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

def autocorrected_value(node) 

def autocorrected_value(node)
  case node.type
  when :int
    node.children.last.to_i.to_s
  when :float
    node.children.last.to_f.to_s
  when :str
    autocorrected_value_for_string(node)
  when :sym
    autocorrected_value_for_symbol(node)
  when :array
    autocorrected_value_for_array(node)
  else
    node.source.gsub('"', '\"')
  end
end

def autocorrected_value_for_array(node) 

def autocorrected_value_for_array(node)
  return node.source.gsub('"', '\"') unless node.percent_literal?
  contents_range(node).source.split.to_s.gsub('"', '\"')
end

def autocorrected_value_for_string(node) 

def autocorrected_value_for_string(node)
  if node.source.start_with?("'", '%q')
    node.children.last.inspect[1..-2]
  else
    node.children.last
  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 ends_heredoc_line?(node) 

def ends_heredoc_line?(node)
  grandparent = node.parent.parent
  return false unless grandparent&.dstr_type? && grandparent&.heredoc?
  line = processed_source.lines[node.last_line - 1]
  line.size == node.loc.last_column + 1
end

def in_array_percent_literal?(node) 

def in_array_percent_literal?(node)
  parent = node.parent
  return false unless parent.dstr_type? || parent.dsym_type?
  grandparent = parent.parent
  grandparent&.array_type? && grandparent&.percent_literal?
end

def offending?(node) 

def offending?(node)
  node &&
    !special_keyword?(node) &&
    prints_as_self?(node) &&
    # Special case for Layout/TrailingWhitespace
    !(space_literal?(node) && ends_heredoc_line?(node))
end

def on_interpolation(begin_node) 

def on_interpolation(begin_node)
  final_node = begin_node.children.last
  return unless offending?(final_node)
  # %W and %I split the content into words before expansion
  # treating each interpolation as a word component, so
  # interpolation should not be removed if the expanded value
  # contains a space character.
  expanded_value = autocorrected_value(final_node)
  return if in_array_percent_literal?(begin_node) &&
            /\s/.match?(expanded_value)
  add_offense(final_node) do |corrector|
    return if final_node.dstr_type? # nested, fixed in next iteration
    corrector.replace(final_node.parent, expanded_value)
  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 space_literal?(node) 

def space_literal?(node)
  node.str_type? && node.value.blank?
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