Refactor how group endings are detected in generated C# code (#5686)

* Modify how end tags are encounted in merge code (compiler)

* Modify how end tags are encounted in merge code (generated)

* Modify how end tags are encounted in merge code (library)

* Regenerate generated code through generate_descriptor_proto.sh

csharp/src/AddressBook/Addressbook.cs

@@ -260,9 +260,7 @@ namespace Google.Protobuf.Examples.AddressBook {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -442,9 +440,7 @@ namespace Google.Protobuf.Examples.AddressBook {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 10: {
                 Number = input.ReadString();
@@ -577,9 +573,7 @@ namespace Google.Protobuf.Examples.AddressBook {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             people_.AddEntriesFrom(input, _repeated_people_codec);

csharp/src/Google.Protobuf.Conformance/Conformance.cs

@@ -216,9 +216,7 @@ namespace Conformance {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             failure_.AddEntriesFrom(input, _repeated_failure_codec);
@@ -581,9 +579,7 @@ namespace Conformance {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             ProtobufPayload = input.ReadBytes();
@@ -1001,9 +997,7 @@ namespace Conformance {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             ParseError = input.ReadString();
@@ -1166,9 +1160,7 @@ namespace Conformance {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             UseJspbArrayAnyFormat = input.ReadBool();

csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs

@@ -541,9 +541,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             mapInt32Int32_.AddEntriesFrom(input, _map_mapInt32Int32_codec);
@@ -739,9 +737,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             if (testMap_ == null) {
@@ -865,9 +861,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             mapInt32Message_.AddEntriesFrom(input, _map_mapInt32Message_codec);
@@ -1007,9 +1001,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             map1_.AddEntriesFrom(input, _map_map1_codec);
@@ -1358,9 +1350,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             mapInt32Int32_.AddEntriesFrom(input, _map_mapInt32Int32_codec);
@@ -1541,9 +1531,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             type_.AddEntriesFrom(input, _map_type_codec);
@@ -1678,9 +1666,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             entry_.AddEntriesFrom(input, _map_entry_codec);

csharp/src/Google.Protobuf.Test/TestProtos/TestMessagesProto3.cs

@@ -2895,9 +2895,7 @@ namespace ProtobufTestMessages.Proto3 {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             OptionalInt32 = input.ReadInt32();
@@ -3625,9 +3623,7 @@ namespace ProtobufTestMessages.Proto3 {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 8: {
                 A = input.ReadInt32();
@@ -3768,9 +3764,7 @@ namespace ProtobufTestMessages.Proto3 {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             C = input.ReadInt32();

csharp/src/Google.Protobuf.Test/TestProtos/UnittestCustomOptionsProto3.cs

@@ -352,9 +352,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Field1 = input.ReadString();
@@ -480,9 +478,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -583,9 +579,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -686,9 +680,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -789,9 +781,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -892,9 +882,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -1008,9 +996,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -1111,9 +1097,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -1214,9 +1198,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -1317,9 +1299,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -1420,9 +1400,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -1523,9 +1501,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -1714,9 +1690,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Foo = input.ReadInt32();
@@ -1928,9 +1902,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             if (bar_ == null) {
@@ -2079,9 +2051,7 @@ namespace UnitTest.Issues.TestProtos {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 8: {
                 Waldo = input.ReadInt32();
@@ -2215,9 +2185,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Qux = input.ReadInt32();
@@ -2325,9 +2293,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -2509,9 +2475,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             I = input.ReadInt32();
@@ -2651,9 +2615,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Fieldname = input.ReadInt32();
@@ -2761,9 +2723,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -2895,9 +2855,7 @@ namespace UnitTest.Issues.TestProtos {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 8: {
                 NestedField = input.ReadInt32();

csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportProto3.cs

@@ -167,9 +167,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             D = input.ReadInt32();

csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportPublicProto3.cs

@@ -155,9 +155,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             E = input.ReadInt32();

csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs

@@ -181,9 +181,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -286,9 +284,7 @@ namespace UnitTest.Issues.TestProtos {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
             }
           }
@@ -391,9 +387,7 @@ namespace UnitTest.Issues.TestProtos {
               while ((tag = input.ReadTag()) != 0) {
                 switch(tag) {
                   default:
-                    if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                      return;
-                    }
+                    _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                     break;
                 }
               }
@@ -560,9 +554,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Value = (global::UnitTest.Issues.TestProtos.NegativeEnum) input.ReadEnum();
@@ -677,9 +669,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }
@@ -909,9 +899,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             PrimitiveValue = input.ReadInt32();
@@ -1068,9 +1056,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Item = input.ReadInt32();
@@ -1223,9 +1209,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Types_ = input.ReadInt32();
@@ -1339,9 +1323,7 @@ namespace UnitTest.Issues.TestProtos {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
             }
           }
@@ -1665,9 +1647,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             PlainString = input.ReadString();
@@ -1867,9 +1847,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -2069,9 +2047,7 @@ namespace UnitTest.Issues.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Text = input.ReadString();
@@ -2235,9 +2211,7 @@ namespace UnitTest.Issues.TestProtos {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 8: {
                 X = input.ReadInt32();

csharp/src/Google.Protobuf.Test/TestProtos/UnittestWellKnownTypes.cs

@@ -788,9 +788,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             if (anyField_ == null) {
@@ -1318,9 +1316,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             anyField_.AddEntriesFrom(input, _repeated_anyField_codec);
@@ -2031,9 +2027,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             global::Google.Protobuf.WellKnownTypes.Any subBuilder = new global::Google.Protobuf.WellKnownTypes.Any();
@@ -2544,9 +2538,7 @@ namespace Google.Protobuf.TestProtos {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             anyField_.AddEntriesFrom(input, _map_anyField_codec);

csharp/src/Google.Protobuf/Reflection/Descriptor.cs

@@ -302,9 +302,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             file_.AddEntriesFrom(input, _repeated_file_codec);
@@ -735,9 +733,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -1102,9 +1098,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -1363,9 +1357,7 @@ namespace Google.Protobuf.Reflection {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 8: {
                 Start = input.ReadInt32();
@@ -1568,9 +1560,7 @@ namespace Google.Protobuf.Reflection {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 8: {
                 Start = input.ReadInt32();
@@ -1703,9 +1693,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 7994: {
             uninterpretedOption_.AddEntriesFrom(input, _repeated_uninterpretedOption_codec);
@@ -2212,9 +2200,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -2501,9 +2487,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -2748,9 +2732,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -2966,9 +2948,7 @@ namespace Google.Protobuf.Reflection {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 8: {
                 Start = input.ReadInt32();
@@ -3197,9 +3177,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -3407,9 +3385,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -3759,9 +3735,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -6949,9 +6923,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 18: {
             name_.AddEntriesFrom(input, _repeated_name_codec);
@@ -7164,9 +7136,7 @@ namespace Google.Protobuf.Reflection {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 10: {
                 NamePart_ = input.ReadString();
@@ -7345,9 +7315,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             location_.AddEntriesFrom(input, _repeated_location_codec);
@@ -7655,9 +7623,7 @@ namespace Google.Protobuf.Reflection {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 10:
               case 8: {
@@ -7810,9 +7776,7 @@ namespace Google.Protobuf.Reflection {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             annotation_.AddEntriesFrom(input, _repeated_annotation_codec);
@@ -8063,9 +8027,7 @@ namespace Google.Protobuf.Reflection {
           while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
               default:
-                if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-                  return;
-                }
+                _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
                 break;
               case 10:
               case 8: {

csharp/src/Google.Protobuf/UnknownFieldSet.cs

@@ -260,29 +260,6 @@ namespace Google.Protobuf
             }
             return unknownFields;
         }
-
-        /// <summary>
-        /// Create a new UnknownFieldSet if unknownFields is null.
-        /// Parse a single field from <paramref name="input"/> and merge it
-        /// into unknownFields. If <paramref name="input"/> is configured to discard unknown fields,
-        /// <paramref name="unknownFields"/> will be returned as-is and the field will be skipped.
-        /// </summary>
-        /// <param name="unknownFields">The UnknownFieldSet which need to be merged</param>
-        /// <param name="input">The coded input stream containing the field</param>
-        /// <returns>The merged UnknownFieldSet</returns>
-        public static bool MergeFieldFrom(ref UnknownFieldSet unknownFields, CodedInputStream input)
-        {
-            if (input.DiscardUnknownFields)
-            {
-                input.SkipLastField();
-                return true;
-            }
-            if (unknownFields == null)
-            {
-                unknownFields = new UnknownFieldSet();
-            }
-            return unknownFields.MergeFieldFrom(input);
-        }
 
         /// <summary>
         /// Merges the fields from <paramref name="other"/> into this set.

csharp/src/Google.Protobuf/WellKnownTypes/Any.cs

@@ -292,9 +292,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             TypeUrl = input.ReadString();

csharp/src/Google.Protobuf/WellKnownTypes/Api.cs

@@ -345,9 +345,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -663,9 +661,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -929,9 +925,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();

csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs

@@ -254,9 +254,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Seconds = input.ReadInt64();

csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs

@@ -143,9 +143,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
         }
       }

csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs

@@ -352,9 +352,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             paths_.AddEntriesFrom(input, _repeated_paths_codec);

csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs

@@ -165,9 +165,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             FileName = input.ReadString();

csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs

@@ -189,9 +189,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             fields_.AddEntriesFrom(input, _map_fields_codec);
@@ -515,9 +513,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             kind_ = input.ReadEnum();
@@ -677,9 +673,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             values_.AddEntriesFrom(input, _repeated_values_codec);

csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs

@@ -273,9 +273,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Seconds = input.ReadInt64();

csharp/src/Google.Protobuf/WellKnownTypes/Type.cs

@@ -328,9 +328,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -725,9 +723,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Kind = (global::Google.Protobuf.WellKnownTypes.Field.Types.Kind) input.ReadEnum();
@@ -1104,9 +1100,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -1306,9 +1300,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();
@@ -1488,9 +1480,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Name = input.ReadString();

csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs

@@ -177,9 +177,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 9: {
             Value = input.ReadDouble();
@@ -316,9 +314,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 13: {
             Value = input.ReadFloat();
@@ -455,9 +451,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Value = input.ReadInt64();
@@ -594,9 +588,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Value = input.ReadUInt64();
@@ -733,9 +725,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Value = input.ReadInt32();
@@ -872,9 +862,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Value = input.ReadUInt32();
@@ -1011,9 +999,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 8: {
             Value = input.ReadBool();
@@ -1150,9 +1136,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Value = input.ReadString();
@@ -1289,9 +1273,7 @@ namespace Google.Protobuf.WellKnownTypes {
       while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
           default:
-            if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {
-              return;
-            }
+            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
             break;
           case 10: {
             Value = input.ReadBytes();

src/google/protobuf/compiler/csharp/csharp_helpers.cc

@@ -278,6 +278,19 @@ std::string GetEnumValueName(const std::string& enum_name, const std::string& en
   return result;
 }
 
+uint GetGroupEndTag(const Descriptor* descriptor) {
+  const Descriptor* containing_type = descriptor->containing_type();
+  if (containing_type == NULL) {
+    return 0;
+  }
+  const FieldDescriptor* field = containing_type->FindFieldByName(descriptor->name());
+  if (field != NULL && field->type() == FieldDescriptor::Type::TYPE_GROUP) {
+    return internal::WireFormatLite::MakeTag(field->number(), internal::WireFormatLite::WIRETYPE_LENGTH_DELIMITED);
+  } else {
+    return 0;
+  }
+}
+
 std::string ToCSharpName(const std::string& name, const FileDescriptor* file) {
   std::string result = GetFileNamespace(file);
   if (result != "") {

src/google/protobuf/compiler/csharp/csharp_helpers.h

@@ -118,6 +118,9 @@ inline bool IsMapEntryMessage(const Descriptor* descriptor) {
   return descriptor->options().map_entry();
 }
 
+// Checks if this descriptor is for a group and gets its end tag or 0 if it's not a group
+uint GetGroupEndTag(const Descriptor* descriptor);
+
 // Determines whether we're generating code for the proto representation of
 // descriptors etc, for use in the runtime. This is the only type which is
 // allowed to use proto2 syntax, and it generates internal classes.

src/google/protobuf/compiler/csharp/csharp_message.cc

@@ -63,7 +63,8 @@ MessageGenerator::MessageGenerator(const Descriptor* descriptor,
                                    const Options* options)
     : SourceGeneratorBase(descriptor->file(), options),
       descriptor_(descriptor),
-      has_bit_field_count_(0) {
+      has_bit_field_count_(0),
+      end_tag_(GetGroupEndTag(descriptor)) {
   // fields by number
   for (int i = 0; i < descriptor_->field_count(); i++) {
     fields_by_number_.push_back(descriptor_->field(i));
@@ -539,10 +540,14 @@ void MessageGenerator::GenerateMergingMethods(io::Printer* printer) {
   } else {
     printer->Print(
       "default:\n"
-      "  if (!pb::UnknownFieldSet.MergeFieldFrom(ref _unknownFields, input)) {\n"
-      "    return;\n"
-      "  }\n"
+      "  _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);\n"
       "  break;\n");
+    if (end_tag_ != 0) {
+      printer->Print(
+        "$end_tag$:\n"
+        "  return;\n",
+        "end_tag", SimpleItoa(end_tag_));
+    }
   }
   for (int i = 0; i < fields_by_number().size(); i++) {
     const FieldDescriptor* field = fields_by_number()[i];

src/google/protobuf/compiler/csharp/csharp_message.h

@@ -59,6 +59,7 @@ class MessageGenerator : public SourceGeneratorBase {
   const Descriptor* descriptor_;
   std::vector<const FieldDescriptor*> fields_by_number_;
   int has_bit_field_count_;
+  uint end_tag_;
 
   void GenerateMessageSerializationMethods(io::Printer* printer);
   void GenerateMergingMethods(io::Printer* printer);