Examples of errors detected by the V3042 diagnostic


V3042. Possible NullReferenceException. The '?.' and '.' operators are used for accessing members of the same object.


Xamarin.Forms

V3042 Possible NullReferenceException. The '?.' and '.' operators are used for accessing members of the Element object Xamarin.Forms.Platform.WinRT MasterDetailPageRenderer.cs 288


void UpdateTitle()
{
  if (Element?.Detail == null)
    return;

   ((ITitleProvider)this).Title =
     (Element.Detail as NavigationPage)
       ?.CurrentPage?.Title ?? Element.Title
                            ?? Element?.Title;
}

.NET Core Libraries (CoreFX)

V3042 Possible NullReferenceException. The '?.' and '.' operators are used for accessing members of the 'sym' object SymbolStore.cs 56


private static void InsertChildNoGrow(Symbol child)
{
  ....
  while (sym?.nextSameName != null)
  {
    sym = sym.nextSameName;
  }

  Debug.Assert(sym != null && sym.nextSameName == null);
  sym.nextSameName = child; // <=
  ....
}

.NET Core Libraries (CoreFX)

V3042 Possible NullReferenceException. The '?.' and '.' operators are used for accessing members of the 'property' object JsonClassInfo.AddProperty.cs 179


internal JsonPropertyInfo CreatePolymorphicProperty(....)
{
  JsonPropertyInfo runtimeProperty
    = CreateProperty(property.DeclaredPropertyType,    // <=
                     runtimePropertyType,
                     property.ImplementedPropertyType, // <=
                     property?.PropertyInfo,           // <=
                     Type,
                     options);
  ....
}

Azure PowerShell

V3042 Possible NullReferenceException. The '?.' and '.' operators are used for accessing members of the 'imageAndOsType' object VirtualMachineScaleSetStrategy.cs 81


internal static ResourceConfig<VirtualMachineScaleSet>
CreateVirtualMachineScaleSetConfig(...., ImageAndOsType imageAndOsType, ....)
{
  ....
  VirtualMachineProfile = new VirtualMachineScaleSetVMProfile
  {
    OsProfile = new VirtualMachineScaleSetOSProfile
    {
        ....,
        WindowsConfiguration =
          imageAndOsType.CreateWindowsConfiguration(),  // <=
        ....,
    },
    StorageProfile = new VirtualMachineScaleSetStorageProfile
    {
        ImageReference = imageAndOsType?.Image,  // <=
        DataDisks = DataDiskStrategy.CreateVmssDataDisks(
          imageAndOsType?.DataDiskLuns, dataDisks)  // <=
    },
  },
  ....
}

Azure PowerShell

V3042 Possible NullReferenceException. The '?.' and '.' operators are used for accessing members of the 'existingContacts' object RemoveAzureKeyVaultCertificateContact.cs 123


public override void ExecuteCmdlet()
{
  ....
  List<PSKeyVaultCertificateContact> existingContacts;

  try
  {
    existingContacts = this.DataServiceClient.
                       GetCertificateContacts(VaultName)?.ToList();
  }
  catch (KeyVaultErrorException exception)
  {
    ....
    existingContacts = null;
  }

  foreach (var email in EmailAddress)
  {
    existingContacts.RemoveAll(....);  // <=
  }
  ....
}


Bugs Found

Checked Projects
363
Collected Errors
13 495