ServiceContractGenerator CodeDomProvider duplicate

I am trying to use ServiceCodeGenerator and CodeDomProvider to dynamically create a service reference. When compiling the code using CodeDomProvider it throws the following errors:

Any idea how I can get around this issue?

CS0579: Duplicate 'System.CodeDom.Compiler.GeneratedCodeAttribute' attribute 99 CS0579: Duplicate 'System.Diagnostics.DebuggerStepThroughAttribute' attribute 101 CS0579: Duplicate 'System.CodeDom.Compiler.GeneratedCodeAttribute' attribute 191 CS0579: Duplicate 'System.Diagnostics.DebuggerStepThroughAttribute' attribute 193

The code is below:

object proxyInstance = null;
    // Define the WSDL Get address, contract name and parameters, with this we can extract WSDL details any time
    Uri address = new Uri("url");
    // For HttpGet endpoints use a Service WSDL address a mexMode of .HttpGet and for MEX endpoints use a MEX address and a mexMode of .MetadataExchange
    MetadataExchangeClientMode mexMode = MetadataExchangeClientMode.HttpGet;
    string contractName = "IService1";
    // Get the metadata file from the service.
    MetadataExchangeClient metadataExchangeClient = new MetadataExchangeClient(address, mexMode);
    metadataExchangeClient.ResolveMetadataReferences = true;

    //Trust all certificates
    System.Net.ServicePointManager.ServerCertificateValidationCallback = ((sender, certificate, chain, sslPolicyErrors) => true);
    //One can also provide credentials if service needs that by the help following two lines.
    ICredentials networkCredential = new NetworkCredential("user", "pass", "domain");
    metadataExchangeClient.HttpCredentials = networkCredential;   

     //Gets the meta data information of the service.
    MetadataSet metadataSet = metadataExchangeClient.GetMetadata();
    // Import all contracts and endpoints.
    WsdlImporter wsdlImporter = new WsdlImporter(metadataSet);
    //Import all contracts.
    Collection<ContractDescription> contracts = wsdlImporter.ImportAllContracts();
    //Import all end points.
    ServiceEndpointCollection allEndpoints = wsdlImporter.ImportAllEndpoints();
    // Generate type information for each contract.
    ServiceContractGenerator serviceContractGenerator = new ServiceContractGenerator(); 

    //Dictinary has been defined to keep all the contract endpoints present, contract name is key of the dictionary item.
    var endpointsForContracts = new Dictionary<string, IEnumerable<ServiceEndpoint>>(); 

    foreach (ContractDescription contract in contracts)
    {

        serviceContractGenerator.GenerateServiceContractType(contract);
        // Keep a list of each contract's endpoints.
        endpointsForContracts[contract.Name] = allEndpoints.Where(ep => ep.Contract.Name == contract.Name).ToList();
    } 

    // Generate a code file for the contracts.
    CodeGeneratorOptions codeGeneratorOptions = new CodeGeneratorOptions();
    codeGeneratorOptions.BracingStyle = "C"; 

    // Create Compiler instance of a specified language.
    CodeDomProvider codeDomProvider = CodeDomProvider.CreateProvider("CSharp"); 

    // Adding WCF-related assemblies references as copiler parameters, so as to do the compilation of particular service contract.
    //CompilerParameters compilerParameters = new CompilerParameters(new string[] { "System.dll", "System.ServiceModel.dll", "System.Runtime.Serialization.dll" });
    CompilerParameters compilerParameters = new CompilerParameters(new string[] {  "System.dll", "System.ServiceModel.dll", "System.Runtime.Serialization.dll" });

    compilerParameters.GenerateInMemory = true;
    compilerParameters.WarningLevel = 1;

    compilerResults = codeDomProvider.CompileAssemblyFromDom(compilerParameters, serviceContractGenerator.TargetCompileUnit);

    if (compilerResults.Errors.Count <= 0)