[Translation] Make DocumentTranslationError a struct

sdk/translation/Azure.AI.Translation.Document/api/Azure.AI.Translation.Document.netstandard2.0.cs

@@ -52,9 +52,11 @@ public enum ServiceVersion
             V1_0 = 1,
         }
     }
-    public partial class DocumentTranslationError
+    [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+    public readonly partial struct DocumentTranslationError
     {
-        internal DocumentTranslationError() { }
+        private readonly object _dummy;
+        private readonly int _dummyPrimitive;
         public Azure.AI.Translation.Document.DocumentTranslationErrorCode ErrorCode { get { throw null; } }
         public string Message { get { throw null; } }
         public string Target { get { throw null; } }
@@ -197,7 +199,7 @@ internal TranslationStatus() { }
         public int DocumentsNotStarted { get { throw null; } }
         public int DocumentsSucceeded { get { throw null; } }
         public int DocumentsTotal { get { throw null; } }
-        public Azure.AI.Translation.Document.DocumentTranslationError Error { get { throw null; } }
+        public Azure.AI.Translation.Document.DocumentTranslationError? Error { get { throw null; } }
         public string Id { get { throw null; } }
         public System.DateTimeOffset LastModified { get { throw null; } }
         public Azure.AI.Translation.Document.DocumentTranslationStatus Status { get { throw null; } }

sdk/translation/Azure.AI.Translation.Document/src/DocumentTranslationError.cs

@@ -10,15 +10,26 @@ namespace Azure.AI.Translation.Document
     /// Represents an error that occurred during a translation operation.
     /// </summary>
     [CodeGenModel("TranslationError")]
-    public partial class DocumentTranslationError
+    public readonly partial struct DocumentTranslationError
     {
         /// <summary>
         /// Error code that serves as an indicator of the HTTP error code.
         /// </summary>
         [CodeGenMember("Code")]
         public DocumentTranslationErrorCode ErrorCode { get; }
 
-        internal InnerTranslationError InnerError { get; }
+        /// <summary>
+        /// Message that contains more information about the reason of the error.
+        /// </summary>
+        public string Message { get; }
+
+        /// <summary>
+        /// Gets the source of the error.
+        /// For example it would be 'documents' or 'document id' in case of invalid document.
+        /// </summary>
+        public string Target { get; }
+
+        internal readonly InnerTranslationError InnerError { get; }
 
         internal DocumentTranslationError(DocumentTranslationErrorCode errorCode, string message, string target, InnerTranslationError innerError)
         {
@@ -35,6 +46,8 @@ internal DocumentTranslationError(DocumentTranslationErrorCode errorCode, string
                 Message = message;
                 Target = target;
             }
+
+            InnerError = null;
         }
     }
 }

sdk/translation/Azure.AI.Translation.Document/src/DocumentTranslationOperation.cs

@@ -299,7 +299,7 @@ private async ValueTask<Response> UpdateStatusAsync(bool async, CancellationToke
                     }
                     else if (update.Value.Status == DocumentTranslationStatus.ValidationFailed)
                     {
-                        DocumentTranslationError error = update.Value.Error;
+                        DocumentTranslationError error = (DocumentTranslationError)update.Value.Error;
                         _requestFailedException = _diagnostics.CreateRequestFailedException(_response, error.Message, error.ErrorCode.ToString(), CreateAdditionalInformation(error));
                         _hasCompleted = true;
                         throw _requestFailedException;