C# Proto2 feature : Field presence and default values (#4642)

* Compiler changes

* Generated code changes

* Library changes

* Compiler style changes

* Generated style changes

* Fix Windows build errors

* Implement changes from review

* Reintroduce proto2 check

* Compiler changes (required handling review)

* Generated code changes (required handling review)

* Library changes (required handling review

* Field presence rewrite (compiler changes)

* Field presence rewrite (generated code changes)

* Compiler comment

* IFieldAccessor.HasValue library implementation

* Remove Clear methods and default values from proto3 code (Compiler)

* Remove Clear methods and default values from proto3 code (Generated)

* Remove Clear methods and default values from proto3 code (Library)

* Fix distcheck error

* Rewrite default string values to use base64 and convert

* Library changes (IMessage2)

* Compiler changes (IMessage2)

* Generated changes (IMessage2)

* Rebased and regenerated

* Compiler changes (initialized extension)

* Generated changes (initialized extension)

* Library changes (initialized extension)

* Refactor MessageExtensions.IsRequired

* Move string default value creator and bytes default value creator back to seperate methods

* Dead code cleanup

* Fixed segmentation fault
Removed unused header method declarations

1 files changed, 3 insertions, 3 deletions

diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs b/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs
index 51715a0c..6d3cd026 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs
@@ -724,7 +724,7 @@ namespace Google.Protobuf.TestProtos {
       }
       if (other.testMap_ != null) {
         if (testMap_ == null) {
-          testMap_ = new global::Google.Protobuf.TestProtos.TestMap();
+          TestMap = new global::Google.Protobuf.TestProtos.TestMap();
         }
         TestMap.MergeFrom(other.TestMap);
       }
@@ -741,9 +741,9 @@ namespace Google.Protobuf.TestProtos {
             break;
           case 10: {
             if (testMap_ == null) {
-              testMap_ = new global::Google.Protobuf.TestProtos.TestMap();
+              TestMap = new global::Google.Protobuf.TestProtos.TestMap();
             }
-            input.ReadMessage(testMap_);
+            input.ReadMessage(TestMap);
             break;
           }
         }