Plugin input with --plugin in customArguments does not work

[totoyoyo]

Using the --plugin option in verificationBackends customArguments does not load the plugin. I looked into the code and there seems to be a ASTGenerator class that loads all the plugins prior to any verifier. However, this means the verifier args like --plugin are not considered, and only the default plugins in Silver are loaded.

For example:

"viperSettings.verificationBackends": [
        {
            "v": "674a514867b1",
            "name": "silicon",
            "type": "silicon",
            "paths": [],
            "engine": "ViperServer",
            "timeout": 100000,
            "stages": [
                {
                    "name": "verify",
                    "isVerification": true,
                    "mainMethod": "viper.silicon.SiliconRunner",
                    "customArguments": "--plugin someRandomPluginClass --z3Exe $z3Exe$ $disableCaching$ $fileToVerify$"
                }
            ],
            "stoppingTimeout": 5000
        }]

The argument provided to --plugin is ignored entirely. Even providing a non-existent class does not have an effect, and there are no error messages.