Generated code changes for previous commit.

19 files changed, 113 insertions, 339 deletions

diff --git a/csharp/src/AddressBook/Addressbook.cs b/csharp/src/AddressBook/Addressbook.cs
index 571478f6..85fa2977 100644
--- a/csharp/src/AddressBook/Addressbook.cs
+++ b/csharp/src/AddressBook/Addressbook.cs
@@ -186,10 +186,8 @@ namespace Google.Protobuf.Examples.AddressBook {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -334,10 +332,8 @@ namespace Google.Protobuf.Examples.AddressBook {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
@@ -442,10 +438,8 @@ namespace Google.Protobuf.Examples.AddressBook {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf.Conformance/Conformance.cs b/csharp/src/Google.Protobuf.Conformance/Conformance.cs
index db0c1225..50a6756c 100644
--- a/csharp/src/Google.Protobuf.Conformance/Conformance.cs
+++ b/csharp/src/Google.Protobuf.Conformance/Conformance.cs
@@ -318,10 +318,8 @@ namespace Conformance {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -556,10 +554,8 @@ namespace Conformance {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1830,10 +1826,8 @@ namespace Conformance {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2259,10 +2253,8 @@ namespace Conformance {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
@@ -2378,10 +2370,8 @@ namespace Conformance {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs b/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs
index db28213c..f6835c4b 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs
@@ -473,10 +473,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -647,10 +645,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -749,10 +745,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -862,10 +856,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1161,10 +1153,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1316,10 +1306,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1425,10 +1413,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportProto3.cs b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportProto3.cs
index ae6e3a3f..646a01a2 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportProto3.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportProto3.cs
@@ -136,10 +136,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportPublicProto3.cs b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportPublicProto3.cs
index 103ea8bb..225775a3 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportPublicProto3.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportPublicProto3.cs
@@ -122,10 +122,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs
index 4e154456..1bf40ead 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs
@@ -139,10 +139,8 @@ namespace UnitTest.Issues.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -221,10 +219,8 @@ namespace UnitTest.Issues.TestProtos {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
@@ -303,10 +299,8 @@ namespace UnitTest.Issues.TestProtos {
 
             public void MergeFrom(pb::CodedInputStream input) {
               uint tag;
-              while (input.ReadTag(out tag)) {
+              while ((tag = input.ReadTag()) != 0) {
                 switch(tag) {
-                  case 0:
-                    throw pb::InvalidProtocolBufferException.InvalidTag();
                   default:
                     if (pb::WireFormat.IsEndGroupTag(tag)) {
                       return;
@@ -444,10 +438,8 @@ namespace UnitTest.Issues.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -539,10 +531,8 @@ namespace UnitTest.Issues.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -737,10 +727,8 @@ namespace UnitTest.Issues.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -869,10 +857,8 @@ namespace UnitTest.Issues.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -998,10 +984,8 @@ namespace UnitTest.Issues.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1088,10 +1072,8 @@ namespace UnitTest.Issues.TestProtos {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
@@ -1358,10 +1340,8 @@ namespace UnitTest.Issues.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestProto3.cs b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestProto3.cs
index 9b4501c5..58e5be65 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestProto3.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestProto3.cs
@@ -1208,10 +1208,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1545,10 +1543,8 @@ namespace Google.Protobuf.TestProtos {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
@@ -1699,10 +1695,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1821,10 +1815,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1928,10 +1920,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2013,10 +2003,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2119,10 +2107,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2251,10 +2237,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2387,10 +2371,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2504,10 +2486,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2639,10 +2619,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2878,10 +2856,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3087,10 +3063,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3232,10 +3206,8 @@ namespace Google.Protobuf.TestProtos {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
@@ -3348,10 +3320,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3455,10 +3425,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3554,10 +3522,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3661,10 +3627,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3768,10 +3732,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3875,10 +3837,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3982,10 +3942,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -4089,10 +4047,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -4196,10 +4152,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -4303,10 +4257,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -4483,10 +4435,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -4777,10 +4727,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -5124,10 +5072,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -5359,10 +5305,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -5492,10 +5436,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -5577,10 +5519,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -5658,10 +5598,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -5739,10 +5677,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -5820,10 +5756,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -5901,10 +5835,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -5982,10 +5914,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestWellKnownTypes.cs b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestWellKnownTypes.cs
index b05c80c1..0840fa27 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestWellKnownTypes.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestWellKnownTypes.cs
@@ -676,10 +676,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1135,10 +1133,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1758,10 +1754,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2208,10 +2202,8 @@ namespace Google.Protobuf.TestProtos {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/Reflection/DescriptorProtoFile.cs b/csharp/src/Google.Protobuf/Reflection/DescriptorProtoFile.cs
index a12e70f8..d66bdb80 100644
--- a/csharp/src/Google.Protobuf/Reflection/DescriptorProtoFile.cs
+++ b/csharp/src/Google.Protobuf/Reflection/DescriptorProtoFile.cs
@@ -239,10 +239,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -538,10 +536,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -834,10 +830,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1003,10 +997,8 @@ namespace Google.Protobuf.Reflection {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
@@ -1136,10 +1128,8 @@ namespace Google.Protobuf.Reflection {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
@@ -1431,10 +1421,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1606,10 +1594,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1752,10 +1738,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1917,10 +1901,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2074,10 +2056,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2305,10 +2285,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2735,10 +2713,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -2990,10 +2966,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3237,10 +3211,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3422,10 +3394,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3551,10 +3521,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3676,10 +3644,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -3801,10 +3767,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -4036,10 +4000,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -4190,10 +4152,8 @@ namespace Google.Protobuf.Reflection {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
@@ -4298,10 +4258,8 @@ namespace Google.Protobuf.Reflection {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -4470,10 +4428,8 @@ namespace Google.Protobuf.Reflection {
 
         public void MergeFrom(pb::CodedInputStream input) {
           uint tag;
-          while (input.ReadTag(out tag)) {
+          while ((tag = input.ReadTag()) != 0) {
             switch(tag) {
-              case 0:
-                throw pb::InvalidProtocolBufferException.InvalidTag();
               default:
                 if (pb::WireFormat.IsEndGroupTag(tag)) {
                   return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Any.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Any.cs
index 4352c16a..9fc653b0 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Any.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Any.cs
@@ -147,10 +147,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Api.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Api.cs
index a5d48166..8a94e7b0 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Api.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Api.cs
@@ -210,10 +210,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -438,10 +436,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs
index 1ca33dce..d74636d4 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs
@@ -148,10 +148,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs
index 0d948e38..0f1d7f50 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs
@@ -103,10 +103,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs b/csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs
index 58dbc7fa..9bd47a96 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs
@@ -117,10 +117,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs b/csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs
index 5566b5ce..ae79884f 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/SourceContext.cs
@@ -126,10 +126,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs
index 72bd16d4..ea8b1055 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs
@@ -136,10 +136,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -391,10 +389,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -521,10 +517,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs
index c3e5383e..89355bdc 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs
@@ -148,10 +148,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Type.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Type.cs
index 862caf82..36116a65 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Type.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Type.cs
@@ -223,10 +223,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -495,10 +493,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -717,10 +713,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -875,10 +869,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -1015,10 +1007,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs
index 2b3814cc..19ed599d 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs
@@ -135,10 +135,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -242,10 +240,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -349,10 +345,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -456,10 +450,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -563,10 +555,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -670,10 +660,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -777,10 +765,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -884,10 +870,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;
@@ -991,10 +975,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public void MergeFrom(pb::CodedInputStream input) {
       uint tag;
-      while (input.ReadTag(out tag)) {
+      while ((tag = input.ReadTag()) != 0) {
         switch(tag) {
-          case 0:
-            throw pb::InvalidProtocolBufferException.InvalidTag();
           default:
             if (pb::WireFormat.IsEndGroupTag(tag)) {
               return;