module RuboCop::Cop::AutocorrectUnlessChangingAST

def autocorrect(node)
  current_buffer_src = processed_source.buffer.source
  replaced_range = node.loc.expression
  pre = current_buffer_src[0...replaced_range.begin_pos]
  post = current_buffer_src[replaced_range.end_pos..-1]
  new_buffer_src = pre + rewrite_node(node) + post
  # Make the correction only if it doesn't change the AST for the buffer.
  if processed_source.ast != ProcessedSource.new(new_buffer_src).ast
    return
  end
  correction(node)
end

def rewrite_node(node)
  ps = ProcessedSource.new(node.loc.expression.source)
  c = correction(ps.ast)
  Corrector.new(ps.buffer, [c]).rewrite
end