index_name_for_remove

# File activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb, line 991
        def index_name_for_remove(table_name, options = {})
          index_name = index_name(table_name, options)

          unless index_name_exists?(table_name, index_name, true)
            if options.is_a?(Hash) && options.has_key?(:name)
              options_without_column = options.dup
              options_without_column.delete :column
              index_name_without_column = index_name(table_name, options_without_column)

              return index_name_without_column if index_name_exists?(table_name, index_name_without_column, false)
            end

            raise ArgumentError, "Index name '#{index_name}' on table '#{table_name}' does not exist"
          end

          index_name
        end