class RuboCop::Cop::Style::IndentArray

spaces) more than the start of the line where the opening bracket is.
Array literals shall have their first element indented one step (2
cop.
lines. The other elements’ indentations are handled by the AlignArray
literal where the opening bracket and the first element are on separate
This cops checks the indentation of the first element in an array

def check_first_pair(first_pair, left_bracket) 

def check_first_pair(first_pair, left_bracket)
  return if first_pair.nil?
  expr = first_pair.loc.expression
  return if expr.line == left_bracket.line
  base_column = left_bracket.source_line =~ /\S/
  expected_column = base_column + IndentationWidth::CORRECT_INDENTATION
  @column_delta = expected_column - expr.column
  return if @column_delta == 0
  msg = format('Use %d spaces for indentation in an array, relative ' \
               'to the start of the line where the left bracket is.',
               IndentationWidth::CORRECT_INDENTATION)
  add_offense(first_pair, :expression, msg)
end

def check_right_bracket(node, first_pair, left_bracket) 

def check_right_bracket(node, first_pair, left_bracket)
  right_bracket = node.loc.end
  column = right_bracket.column
  return if right_bracket.source_line[0...column] =~ /\S/
  if first_pair && first_pair.loc.expression.line == left_bracket.line
    base_column = left_bracket.column
    expected_indentation = 'the left bracket'
  else
    base_column = left_bracket.source_line =~ /\S/
    expected_indentation =
      'the start of the line where the left bracket is'
  end
  @column_delta = base_column - column
  return if @column_delta == 0
  add_offense(right_bracket, right_bracket,
              'Indent the right bracket the same as ' +
              expected_indentation + '.')
end

def on_array(node) 

def on_array(node)
  left_bracket = node.loc.begin
  return if left_bracket.nil?
  first_pair = node.children.first
  check_first_pair(first_pair, left_bracket)
  check_right_bracket(node, first_pair, left_bracket)
end