Microsoft.Network/applicationGateways don't support SystemAssigned identity

The ARM template reference schema documentation and in this GitHub have information stating that application gateway supports ‘systemAssigned’ & ‘systemAssigned, userAssigned’ identity enums when in fact it will throw an ARM template validation error stating that Resource type ‘Microsoft.Network/applicationGateways’ does not support creation of ‘SystemAssigned’ resource identity. The supported types are ‘UserAssigned’. This goes all the way back through the every API version as far as I can tell.

Raw Error:

{
  "telemetryId": "e82a70bf-4d83-4c98-82da-ca76e6efef51",
  "bladeInstanceId": "Blade_0d3945635d134b24b3518f1dd69770c4_54_0",
  "galleryItemId": "Microsoft.Template",
  "createBlade": "DeployToAzure",
  "code": "CannotSetResourceIdentity",
  "message": "Resource type 'Microsoft.Network/applicationGateways' does not support creation of 'SystemAssigned' resource identity. The supported types are 'UserAssigned'."
}

Incorrect Documentation/Schemas: https://docs.microsoft.com/en-us/azure/templates/microsoft.network/2019-11-01/applicationgateways#managedserviceidentity-object https://github.com/Azure/azure-resource-manager-schemas/blob/master/schemas/2019-11-01/Microsoft.Network.json#L10190 https://github.com/Azure/azure-resource-manager-schemas/blob/master/schemas/2019-11-01/Microsoft.Network.json#L10192 https://github.com/Azure/azure-resource-manager-schemas/blob/master/schemas/2019-11-01/Microsoft.Network.json#L10195

[anthony-c-martin]

I’ve raised https://github.com/Azure/azure-rest-api-specs/issues/16632 for this

[aholler2]

Closing as issue is now tracked in https://github.com/Azure/azure-rest-api-specs/issues/16632