SyntaxSuggest::CodeBlock#valid?

# File tmp/rubies/ruby-3.4.1/lib/syntax_suggest/code_block.rb, line 75
def valid?
  if @valid == UNSET
    # Performance optimization
    #
    # If all the lines were previously hidden
    # and we expand to capture additional empty
    # lines then the result cannot be invalid
    #
    # That means there's no reason to re-check all
    # lines with the parser (which is expensive).
    # Benchmark in commit message
    @valid = if lines.all? { |l| l.hidden? || l.empty? }
      true
    else
      SyntaxSuggest.valid?(lines.map(&:original).join)
    end
  else
    @valid
  end
end