ErrorHighlight::Spotter#spot_op_cdecl

# File tmp/rubies/ruby-4.1.0-preview1/lib/error_highlight/base.rb, line 663
def spot_op_cdecl
  nd_lhs, op, _nd_rhs = @node.children
  *nd_parent_lhs, _const = nd_lhs.children
  if @name == op
    fetch_line(nd_lhs.last_lineno)
    if @snippet.match(/\G\s*(#{ Regexp.quote(op) })=/, nd_lhs.last_column)
      @beg_column = $~.begin(1)
      @end_column = $~.end(1)
    end
  else
    # constant access error
    @end_column = nd_lhs.last_column
    if nd_parent_lhs.empty? # example: ::C += 1
      if nd_lhs.first_lineno == nd_lhs.last_lineno
        fetch_line(nd_lhs.last_lineno)
        @beg_column = nd_lhs.first_column
      end
    else # example: Foo::Bar::C += 1
      if nd_parent_lhs.last.last_lineno == nd_lhs.last_lineno
        fetch_line(nd_lhs.last_lineno)
        @beg_column = nd_parent_lhs.last.last_column
      end
    end
  end
end