less-loader 报错：27:9: Unknown word

Question

报的错是：
27:9: Unknown word

也就是下面这段less

.iconColor() {
    color: rgb(79, 192, 141);
}

然后我在下面使用

.side-bar-wrap {
  .iconColor;
}

webpack的配置如下：

 {
                test: /\.less$/,
                include: [
                    path.resolve(__dirname, 'src/styles/backend')
                ],
                loader: ExtractTextPlugin.extract('style-loader', 'css-loader?modules&localIdentName=[local]-[hash:base64:5]', 'less-loader')
            }, {
                test: /\.less$/,
                exclude: [
                    path.resolve(__dirname, 'src/styles/backend')
                ],
                loader: ExtractTextPlugin.extract('style-loader', 'css-loader?sourceMap!autoprefixer-loader!' + `less`)
            }