[406] Scss using custom alias failed

There is no problem with using the default alias in scss, but using a custom alias error,It is normal to use this alias in the script.

extend (config) {
        config.resolve.alias['~mixin'] = path.resolve(__dirname, './assets/style/helpers/mixin.scss')
}

Module build failed: 
    @import "~mixin";
^
      File to import not found or unreadable: ~mixin.