ProgramNode(0...24)( [:a], StatementsNode(0...24)( [LocalVariableAndWriteNode(0...7)( (0...1), (2...5), CallNode(6...7)(nil, nil, (6...7), nil, nil, nil, nil, 2, "b"), :a, 0 ), LocalVariableOperatorWriteNode(9...15)( (9...10), (11...13), CallNode(14...15)(nil, nil, (14...15), nil, nil, nil, nil, 2, "b"), :a, :+, 0 ), LocalVariableOrWriteNode(17...24)( (17...18), (19...22), CallNode(23...24)(nil, nil, (23...24), nil, nil, nil, nil, 2, "b"), :a, 0 )] ) )