Module declaration in product file

import qbs
import qbs.File
import qbs.FileInfo


Product {
    type: "application"
    files: "main.cpp"

    FileTagger {
        pattern: "*.cpp"
        fileTags: ["cpp"]
    }

    Rule {
        id: compiler
        inputs: ['cpp']
        auxiliaryInputs: ['hpp']
        condition: true
        explicitlyDependsOn:  ['cpp']

        Artifact {
            fileTags: ["cppcopy","application"]
            fileName: input.completeBaseName+".cpp"
        }

        prepare: {
            var cmd = new JavaScriptCommand();
            cmd.description = "Copy Example File: '" 
                              + input.fileName + "'";
            cmd.highlight = "codegen";
            cmd.sourceCode = function() {
                var sourcepath = input.fileName;
                File.copy( sourcepath , output.fileName);
            }
            return cmd;
        }
    }

    Module {
        name: "testmodule"
        property string warningLevel
    }
}

ERROR: language/projectresolver.cpp:1005 ASSERT: f