diff --git a/src/AddressBook/AddressBookProtos.cs b/src/AddressBook/AddressBookProtos.cs
index 2ed0a110a7..580ca6c503 100644
--- a/src/AddressBook/AddressBookProtos.cs
+++ b/src/AddressBook/AddressBookProtos.cs
@@ -206,10 +206,10 @@ namespace Google.ProtocolBuffers.Examples.AddressBook {
         public static PhoneNumber ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static PhoneNumber ParseFrom(pb::CodedInputStream input) {
+        public static PhoneNumber ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static PhoneNumber ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static PhoneNumber ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -281,11 +281,11 @@ namespace Google.ProtocolBuffers.Examples.AddressBook {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -497,10 +497,10 @@ namespace Google.ProtocolBuffers.Examples.AddressBook {
     public static Person ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static Person ParseFrom(pb::CodedInputStream input) {
+    public static Person ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static Person ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static Person ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -579,11 +579,11 @@ namespace Google.ProtocolBuffers.Examples.AddressBook {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -824,10 +824,10 @@ namespace Google.ProtocolBuffers.Examples.AddressBook {
     public static AddressBook ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static AddressBook ParseFrom(pb::CodedInputStream input) {
+    public static AddressBook ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static AddressBook ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static AddressBook ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -897,11 +897,11 @@ namespace Google.ProtocolBuffers.Examples.AddressBook {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtoGen/MessageGenerator.cs b/src/ProtoGen/MessageGenerator.cs
index 228dcf8829..13c6fad05c 100644
--- a/src/ProtoGen/MessageGenerator.cs
+++ b/src/ProtoGen/MessageGenerator.cs
@@ -423,11 +423,11 @@ namespace Google.ProtocolBuffers.ProtoGen
                 ClassName);
             writer.WriteLine("  return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();");
             writer.WriteLine("}");
-            writer.WriteLine("public static {0} ParseFrom(pb::CodedInputStream input) {{", ClassName);
+            writer.WriteLine("public static {0} ParseFrom(pb::ICodedInputStream input) {{", ClassName);
             writer.WriteLine("  return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();");
             writer.WriteLine("}");
             writer.WriteLine(
-                "public static {0} ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {{",
+                "public static {0} ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {{",
                 ClassName);
             writer.WriteLine("  return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();");
             writer.WriteLine("}");
@@ -604,12 +604,12 @@ namespace Google.ProtocolBuffers.ProtoGen
             List<FieldDescriptor> sortedFields = new List<FieldDescriptor>(Descriptor.Fields);
             sortedFields.Sort((f1, f2) => f1.FieldNumber.CompareTo(f2.FieldNumber));
 
-            writer.WriteLine("public override Builder MergeFrom(pb::CodedInputStream input) {");
+            writer.WriteLine("public override Builder MergeFrom(pb::ICodedInputStream input) {");
             writer.WriteLine("  return MergeFrom(input, pb::ExtensionRegistry.Empty);");
             writer.WriteLine("}");
             writer.WriteLine();
             writer.WriteLine(
-                "public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {");
+                "public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {");
             writer.Indent();
             if (!UseLiteRuntime)
             {
diff --git a/src/ProtocolBuffers.Test/AbstractMessageTest.cs b/src/ProtocolBuffers.Test/AbstractMessageTest.cs
index e300ac944a..f1dbda3f67 100644
--- a/src/ProtocolBuffers.Test/AbstractMessageTest.cs
+++ b/src/ProtocolBuffers.Test/AbstractMessageTest.cs
@@ -465,7 +465,7 @@ namespace Google.ProtocolBuffers
                     return this;
                 }
 
-                public override Builder MergeFrom(CodedInputStream input, ExtensionRegistry extensionRegistry)
+                public override Builder MergeFrom(ICodedInputStream input, ExtensionRegistry extensionRegistry)
                 {
                     wrappedBuilder.WeakMergeFrom(input, extensionRegistry);
                     return this;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestCSharpOptionsProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestCSharpOptionsProtoFile.cs
index 55f52f79a6..ae057e07e1 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestCSharpOptionsProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestCSharpOptionsProtoFile.cs
@@ -175,10 +175,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static OptionsMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static OptionsMessage ParseFrom(pb::CodedInputStream input) {
+    public static OptionsMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static OptionsMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static OptionsMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -253,11 +253,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestCustomOptionsProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestCustomOptionsProtoFile.cs
index 96c8a760fd..b133581393 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestCustomOptionsProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestCustomOptionsProtoFile.cs
@@ -498,10 +498,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMessageWithCustomOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMessageWithCustomOptions ParseFrom(pb::CodedInputStream input) {
+    public static TestMessageWithCustomOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMessageWithCustomOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMessageWithCustomOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -570,11 +570,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -707,10 +707,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static CustomOptionFooRequest ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static CustomOptionFooRequest ParseFrom(pb::CodedInputStream input) {
+    public static CustomOptionFooRequest ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static CustomOptionFooRequest ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static CustomOptionFooRequest ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -776,11 +776,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -890,10 +890,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static CustomOptionFooResponse ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static CustomOptionFooResponse ParseFrom(pb::CodedInputStream input) {
+    public static CustomOptionFooResponse ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static CustomOptionFooResponse ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static CustomOptionFooResponse ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -959,11 +959,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1088,10 +1088,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static DummyMessageContainingEnum ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static DummyMessageContainingEnum ParseFrom(pb::CodedInputStream input) {
+    public static DummyMessageContainingEnum ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static DummyMessageContainingEnum ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static DummyMessageContainingEnum ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1157,11 +1157,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1271,10 +1271,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static DummyMessageInvalidAsOptionType ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static DummyMessageInvalidAsOptionType ParseFrom(pb::CodedInputStream input) {
+    public static DummyMessageInvalidAsOptionType ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static DummyMessageInvalidAsOptionType ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static DummyMessageInvalidAsOptionType ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1340,11 +1340,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1454,10 +1454,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static CustomOptionMinIntegerValues ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static CustomOptionMinIntegerValues ParseFrom(pb::CodedInputStream input) {
+    public static CustomOptionMinIntegerValues ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static CustomOptionMinIntegerValues ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static CustomOptionMinIntegerValues ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1523,11 +1523,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1637,10 +1637,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static CustomOptionMaxIntegerValues ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static CustomOptionMaxIntegerValues ParseFrom(pb::CodedInputStream input) {
+    public static CustomOptionMaxIntegerValues ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static CustomOptionMaxIntegerValues ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static CustomOptionMaxIntegerValues ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1706,11 +1706,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1820,10 +1820,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static CustomOptionOtherValues ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static CustomOptionOtherValues ParseFrom(pb::CodedInputStream input) {
+    public static CustomOptionOtherValues ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static CustomOptionOtherValues ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static CustomOptionOtherValues ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1889,11 +1889,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -2003,10 +2003,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SettingRealsFromPositiveInts ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SettingRealsFromPositiveInts ParseFrom(pb::CodedInputStream input) {
+    public static SettingRealsFromPositiveInts ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SettingRealsFromPositiveInts ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SettingRealsFromPositiveInts ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -2072,11 +2072,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -2186,10 +2186,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SettingRealsFromNegativeInts ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SettingRealsFromNegativeInts ParseFrom(pb::CodedInputStream input) {
+    public static SettingRealsFromNegativeInts ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SettingRealsFromNegativeInts ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SettingRealsFromNegativeInts ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -2255,11 +2255,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -2421,10 +2421,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ComplexOptionType1 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ComplexOptionType1 ParseFrom(pb::CodedInputStream input) {
+    public static ComplexOptionType1 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ComplexOptionType1 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ComplexOptionType1 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -2500,11 +2500,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -2728,10 +2728,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static ComplexOptionType4 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static ComplexOptionType4 ParseFrom(pb::CodedInputStream input) {
+        public static ComplexOptionType4 ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static ComplexOptionType4 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static ComplexOptionType4 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -2800,11 +2800,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -2969,10 +2969,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ComplexOptionType2 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ComplexOptionType2 ParseFrom(pb::CodedInputStream input) {
+    public static ComplexOptionType2 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ComplexOptionType2 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ComplexOptionType2 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3048,11 +3048,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -3320,10 +3320,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static ComplexOptionType5 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static ComplexOptionType5 ParseFrom(pb::CodedInputStream input) {
+        public static ComplexOptionType5 ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static ComplexOptionType5 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static ComplexOptionType5 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -3392,11 +3392,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -3538,10 +3538,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ComplexOptionType3 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ComplexOptionType3 ParseFrom(pb::CodedInputStream input) {
+    public static ComplexOptionType3 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ComplexOptionType3 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ComplexOptionType3 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3613,11 +3613,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -3810,10 +3810,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ComplexOpt6 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ComplexOpt6 ParseFrom(pb::CodedInputStream input) {
+    public static ComplexOpt6 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ComplexOpt6 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ComplexOpt6 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3882,11 +3882,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -4018,10 +4018,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static VariousComplexOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static VariousComplexOptions ParseFrom(pb::CodedInputStream input) {
+    public static VariousComplexOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static VariousComplexOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static VariousComplexOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -4087,11 +4087,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
index 9993960dbc..60a8b8de69 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestEmbedOptimizeForProtoFile.cs
@@ -171,10 +171,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestEmbedOptimizedForSize ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestEmbedOptimizedForSize ParseFrom(pb::CodedInputStream input) {
+    public static TestEmbedOptimizedForSize ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestEmbedOptimizedForSize ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestEmbedOptimizedForSize ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -247,11 +247,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestGoogleSizeProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestGoogleSizeProtoFile.cs
index a4d24b9154..1e9033fb06 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestGoogleSizeProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestGoogleSizeProtoFile.cs
@@ -594,10 +594,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SizeMessage1 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SizeMessage1 ParseFrom(pb::CodedInputStream input) {
+    public static SizeMessage1 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SizeMessage1 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SizeMessage1 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1685,10 +1685,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SizeMessage1SubMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SizeMessage1SubMessage ParseFrom(pb::CodedInputStream input) {
+    public static SizeMessage1SubMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SizeMessage1SubMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SizeMessage1SubMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -2361,10 +2361,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Group1 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Group1 ParseFrom(pb::CodedInputStream input) {
+        public static Group1 ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Group1 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Group1 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -3101,10 +3101,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SizeMessage2 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SizeMessage2 ParseFrom(pb::CodedInputStream input) {
+    public static SizeMessage2 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SizeMessage2 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SizeMessage2 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3915,10 +3915,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SizeMessage2GroupedMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SizeMessage2GroupedMessage ParseFrom(pb::CodedInputStream input) {
+    public static SizeMessage2GroupedMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SizeMessage2GroupedMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SizeMessage2GroupedMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestGoogleSpeedProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestGoogleSpeedProtoFile.cs
index 757ecff335..5bb6df0359 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestGoogleSpeedProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestGoogleSpeedProtoFile.cs
@@ -870,10 +870,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SpeedMessage1 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SpeedMessage1 ParseFrom(pb::CodedInputStream input) {
+    public static SpeedMessage1 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SpeedMessage1 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SpeedMessage1 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1063,11 +1063,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -2447,10 +2447,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SpeedMessage1SubMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SpeedMessage1SubMessage ParseFrom(pb::CodedInputStream input) {
+    public static SpeedMessage1SubMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SpeedMessage1SubMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SpeedMessage1SubMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -2576,11 +2576,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -3450,10 +3450,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Group1 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Group1 ParseFrom(pb::CodedInputStream input) {
+        public static Group1 ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Group1 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Group1 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -3570,11 +3570,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -4576,10 +4576,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SpeedMessage2 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SpeedMessage2 ParseFrom(pb::CodedInputStream input) {
+    public static SpeedMessage2 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SpeedMessage2 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SpeedMessage2 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -4739,11 +4739,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5740,10 +5740,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SpeedMessage2GroupedMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SpeedMessage2GroupedMessage ParseFrom(pb::CodedInputStream input) {
+    public static SpeedMessage2GroupedMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SpeedMessage2GroupedMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SpeedMessage2GroupedMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5842,11 +5842,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestImportLiteProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestImportLiteProtoFile.cs
index 0e890f3327..19d89891f9 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestImportLiteProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestImportLiteProtoFile.cs
@@ -135,10 +135,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ImportMessageLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ImportMessageLite ParseFrom(pb::CodedInputStream input) {
+    public static ImportMessageLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ImportMessageLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ImportMessageLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -202,11 +202,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestImportProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestImportProtoFile.cs
index cbd6cea36c..7fd62591e9 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestImportProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestImportProtoFile.cs
@@ -154,10 +154,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ImportMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ImportMessage ParseFrom(pb::CodedInputStream input) {
+    public static ImportMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ImportMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ImportMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -226,11 +226,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestMessageSetProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestMessageSetProtoFile.cs
index b41a15dcd2..7023d755df 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestMessageSetProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestMessageSetProtoFile.cs
@@ -174,10 +174,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMessageSet ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMessageSet ParseFrom(pb::CodedInputStream input) {
+    public static TestMessageSet ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMessageSet ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMessageSet ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -244,11 +244,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -374,10 +374,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMessageSetContainer ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMessageSetContainer ParseFrom(pb::CodedInputStream input) {
+    public static TestMessageSetContainer ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMessageSetContainer ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMessageSetContainer ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -446,11 +446,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -623,10 +623,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMessageSetExtension1 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMessageSetExtension1 ParseFrom(pb::CodedInputStream input) {
+    public static TestMessageSetExtension1 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMessageSetExtension1 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMessageSetExtension1 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -695,11 +695,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -849,10 +849,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMessageSetExtension2 ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMessageSetExtension2 ParseFrom(pb::CodedInputStream input) {
+    public static TestMessageSetExtension2 ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMessageSetExtension2 ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMessageSetExtension2 ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -921,11 +921,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1122,10 +1122,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Item ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Item ParseFrom(pb::CodedInputStream input) {
+        public static Item ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Item ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Item ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1197,11 +1197,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -1352,10 +1352,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static RawMessageSet ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static RawMessageSet ParseFrom(pb::CodedInputStream input) {
+    public static RawMessageSet ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static RawMessageSet ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static RawMessageSet ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1425,11 +1425,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestNoGenericServicesProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestNoGenericServicesProtoFile.cs
index f72688bb10..99bcf3bd04 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestNoGenericServicesProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestNoGenericServicesProtoFile.cs
@@ -168,10 +168,10 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
     public static TestMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMessage ParseFrom(pb::CodedInputStream input) {
+    public static TestMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -241,11 +241,11 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestOptimizeForProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestOptimizeForProtoFile.cs
index fbbcad96bc..53fe9ef6f0 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestOptimizeForProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestOptimizeForProtoFile.cs
@@ -152,10 +152,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestOptimizedForSize ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestOptimizedForSize ParseFrom(pb::CodedInputStream input) {
+    public static TestOptimizedForSize ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestOptimizedForSize ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestOptimizedForSize ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -325,10 +325,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRequiredOptimizedForSize ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRequiredOptimizedForSize ParseFrom(pb::CodedInputStream input) {
+    public static TestRequiredOptimizedForSize ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRequiredOptimizedForSize ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRequiredOptimizedForSize ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -462,10 +462,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestOptionalOptimizedForSize ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestOptionalOptimizedForSize ParseFrom(pb::CodedInputStream input) {
+    public static TestOptionalOptimizedForSize ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestOptionalOptimizedForSize ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestOptionalOptimizedForSize ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestProtoFile.cs
index d564a02854..5da244d1e4 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestProtoFile.cs
@@ -1151,10 +1151,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static NestedMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1223,11 +1223,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -1375,10 +1375,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static OptionalGroup ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static OptionalGroup ParseFrom(pb::CodedInputStream input) {
+        public static OptionalGroup ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static OptionalGroup ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static OptionalGroup ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1447,11 +1447,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -1599,10 +1599,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static RepeatedGroup ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static RepeatedGroup ParseFrom(pb::CodedInputStream input) {
+        public static RepeatedGroup ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static RepeatedGroup ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static RepeatedGroup ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1671,11 +1671,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -3029,10 +3029,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestAllTypes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestAllTypes ParseFrom(pb::CodedInputStream input) {
+    public static TestAllTypes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestAllTypes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestAllTypes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3326,11 +3326,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5411,10 +5411,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestDeprecatedFields ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestDeprecatedFields ParseFrom(pb::CodedInputStream input) {
+    public static TestDeprecatedFields ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestDeprecatedFields ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestDeprecatedFields ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5483,11 +5483,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5635,10 +5635,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ForeignMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ForeignMessage ParseFrom(pb::CodedInputStream input) {
+    public static ForeignMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ForeignMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ForeignMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5707,11 +5707,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5847,10 +5847,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestAllExtensions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestAllExtensions ParseFrom(pb::CodedInputStream input) {
+    public static TestAllExtensions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestAllExtensions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestAllExtensions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5917,11 +5917,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -6047,10 +6047,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static OptionalGroup_extension ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static OptionalGroup_extension ParseFrom(pb::CodedInputStream input) {
+    public static OptionalGroup_extension ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static OptionalGroup_extension ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static OptionalGroup_extension ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6119,11 +6119,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -6271,10 +6271,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static RepeatedGroup_extension ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static RepeatedGroup_extension ParseFrom(pb::CodedInputStream input) {
+    public static RepeatedGroup_extension ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static RepeatedGroup_extension ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static RepeatedGroup_extension ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6343,11 +6343,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -6481,10 +6481,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestNestedExtension ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestNestedExtension ParseFrom(pb::CodedInputStream input) {
+    public static TestNestedExtension ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestNestedExtension ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestNestedExtension ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6550,11 +6550,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -7199,10 +7199,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRequired ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRequired ParseFrom(pb::CodedInputStream input) {
+    public static TestRequired ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRequired ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRequired ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -7367,11 +7367,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -8263,10 +8263,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRequiredForeign ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRequiredForeign ParseFrom(pb::CodedInputStream input) {
+    public static TestRequiredForeign ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRequiredForeign ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRequiredForeign ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -8342,11 +8342,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -8581,10 +8581,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestForeignNested ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestForeignNested ParseFrom(pb::CodedInputStream input) {
+    public static TestForeignNested ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestForeignNested ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestForeignNested ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -8653,11 +8653,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -8812,10 +8812,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestEmptyMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestEmptyMessage ParseFrom(pb::CodedInputStream input) {
+    public static TestEmptyMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestEmptyMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestEmptyMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -8881,11 +8881,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -8999,10 +8999,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestEmptyMessageWithExtensions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestEmptyMessageWithExtensions ParseFrom(pb::CodedInputStream input) {
+    public static TestEmptyMessageWithExtensions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestEmptyMessageWithExtensions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestEmptyMessageWithExtensions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -9069,11 +9069,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -9189,10 +9189,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMultipleExtensionRanges ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMultipleExtensionRanges ParseFrom(pb::CodedInputStream input) {
+    public static TestMultipleExtensionRanges ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMultipleExtensionRanges ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMultipleExtensionRanges ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -9259,11 +9259,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -9405,10 +9405,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestReallyLargeTagNumber ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestReallyLargeTagNumber ParseFrom(pb::CodedInputStream input) {
+    public static TestReallyLargeTagNumber ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestReallyLargeTagNumber ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestReallyLargeTagNumber ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -9480,11 +9480,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -9670,10 +9670,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRecursiveMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRecursiveMessage ParseFrom(pb::CodedInputStream input) {
+    public static TestRecursiveMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRecursiveMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRecursiveMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -9745,11 +9745,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -9942,10 +9942,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMutualRecursionA ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMutualRecursionA ParseFrom(pb::CodedInputStream input) {
+    public static TestMutualRecursionA ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMutualRecursionA ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMutualRecursionA ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -10014,11 +10014,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -10205,10 +10205,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMutualRecursionB ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMutualRecursionB ParseFrom(pb::CodedInputStream input) {
+    public static TestMutualRecursionB ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMutualRecursionB ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMutualRecursionB ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -10280,11 +10280,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -10507,10 +10507,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Foo ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Foo ParseFrom(pb::CodedInputStream input) {
+        public static Foo ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Foo ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Foo ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -10579,11 +10579,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -10731,10 +10731,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Bar ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Bar ParseFrom(pb::CodedInputStream input) {
+        public static Bar ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Bar ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Bar ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -10803,11 +10803,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -10965,10 +10965,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestDupFieldNumber ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestDupFieldNumber ParseFrom(pb::CodedInputStream input) {
+    public static TestDupFieldNumber ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestDupFieldNumber ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestDupFieldNumber ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -11043,11 +11043,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -11340,10 +11340,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static NestedMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -11417,11 +11417,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -11597,10 +11597,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestNestedMessageHasBits ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestNestedMessageHasBits ParseFrom(pb::CodedInputStream input) {
+    public static TestNestedMessageHasBits ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestNestedMessageHasBits ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestNestedMessageHasBits ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -11669,11 +11669,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -12059,10 +12059,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestCamelCaseFieldNames ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestCamelCaseFieldNames ParseFrom(pb::CodedInputStream input) {
+    public static TestCamelCaseFieldNames ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestCamelCaseFieldNames ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestCamelCaseFieldNames ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -12170,11 +12170,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -12710,10 +12710,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestFieldOrderings ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestFieldOrderings ParseFrom(pb::CodedInputStream input) {
+    public static TestFieldOrderings ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestFieldOrderings ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestFieldOrderings ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -12789,11 +12789,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -13276,10 +13276,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestExtremeDefaultValues ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestExtremeDefaultValues ParseFrom(pb::CodedInputStream input) {
+    public static TestExtremeDefaultValues ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestExtremeDefaultValues ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestExtremeDefaultValues ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -13402,11 +13402,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -13956,10 +13956,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static OneString ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static OneString ParseFrom(pb::CodedInputStream input) {
+    public static OneString ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static OneString ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static OneString ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -14028,11 +14028,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -14181,10 +14181,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static OneBytes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static OneBytes ParseFrom(pb::CodedInputStream input) {
+    public static OneBytes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static OneBytes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static OneBytes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -14253,11 +14253,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -14763,10 +14763,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestPackedTypes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestPackedTypes ParseFrom(pb::CodedInputStream input) {
+    public static TestPackedTypes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestPackedTypes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestPackedTypes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -14888,11 +14888,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -15769,10 +15769,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestUnpackedTypes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestUnpackedTypes ParseFrom(pb::CodedInputStream input) {
+    public static TestUnpackedTypes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestUnpackedTypes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestUnpackedTypes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -15894,11 +15894,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -16461,10 +16461,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestPackedExtensions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestPackedExtensions ParseFrom(pb::CodedInputStream input) {
+    public static TestPackedExtensions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestPackedExtensions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestPackedExtensions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -16531,11 +16531,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -16699,10 +16699,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static DynamicMessageType ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static DynamicMessageType ParseFrom(pb::CodedInputStream input) {
+        public static DynamicMessageType ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static DynamicMessageType ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static DynamicMessageType ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -16771,11 +16771,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -17016,10 +17016,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestDynamicExtensions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestDynamicExtensions ParseFrom(pb::CodedInputStream input) {
+    public static TestDynamicExtensions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestDynamicExtensions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestDynamicExtensions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -17108,11 +17108,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -17596,10 +17596,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRepeatedScalarDifferentTagSizes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRepeatedScalarDifferentTagSizes ParseFrom(pb::CodedInputStream input) {
+    public static TestRepeatedScalarDifferentTagSizes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRepeatedScalarDifferentTagSizes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRepeatedScalarDifferentTagSizes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -17689,11 +17689,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -17998,10 +17998,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static FooRequest ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static FooRequest ParseFrom(pb::CodedInputStream input) {
+    public static FooRequest ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static FooRequest ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static FooRequest ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -18067,11 +18067,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -18181,10 +18181,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static FooResponse ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static FooResponse ParseFrom(pb::CodedInputStream input) {
+    public static FooResponse ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static FooResponse ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static FooResponse ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -18250,11 +18250,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -18364,10 +18364,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static BarRequest ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static BarRequest ParseFrom(pb::CodedInputStream input) {
+    public static BarRequest ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static BarRequest ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static BarRequest ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -18433,11 +18433,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -18547,10 +18547,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static BarResponse ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static BarResponse ParseFrom(pb::CodedInputStream input) {
+    public static BarResponse ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static BarResponse ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static BarResponse ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -18616,11 +18616,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestRpcInterop.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestRpcInterop.cs
index 58ceef7e23..149bb28613 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestRpcInterop.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestRpcInterop.cs
@@ -173,10 +173,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SearchRequest ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SearchRequest ParseFrom(pb::CodedInputStream input) {
+    public static SearchRequest ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SearchRequest ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SearchRequest ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -246,11 +246,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -455,10 +455,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static ResultItem ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static ResultItem ParseFrom(pb::CodedInputStream input) {
+        public static ResultItem ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static ResultItem ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static ResultItem ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -530,11 +530,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -689,10 +689,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static SearchResponse ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static SearchResponse ParseFrom(pb::CodedInputStream input) {
+    public static SearchResponse ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static SearchResponse ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static SearchResponse ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -762,11 +762,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -959,10 +959,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static RefineSearchRequest ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static RefineSearchRequest ParseFrom(pb::CodedInputStream input) {
+    public static RefineSearchRequest ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static RefineSearchRequest ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static RefineSearchRequest ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1035,11 +1035,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers.Test/TestProtos/UnitTestXmlSerializerTestProtoFile.cs b/src/ProtocolBuffers.Test/TestProtos/UnitTestXmlSerializerTestProtoFile.cs
index 2476cf1aed..fc705fd993 100644
--- a/src/ProtocolBuffers.Test/TestProtos/UnitTestXmlSerializerTestProtoFile.cs
+++ b/src/ProtocolBuffers.Test/TestProtos/UnitTestXmlSerializerTestProtoFile.cs
@@ -238,10 +238,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestXmlChild ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestXmlChild ParseFrom(pb::CodedInputStream input) {
+    public static TestXmlChild ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestXmlChild ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestXmlChild ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -314,11 +314,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -490,10 +490,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestXmlNoFields ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestXmlNoFields ParseFrom(pb::CodedInputStream input) {
+    public static TestXmlNoFields ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestXmlNoFields ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestXmlNoFields ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -559,11 +559,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -744,10 +744,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Children ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Children ParseFrom(pb::CodedInputStream input) {
+        public static Children ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Children ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Children ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -820,11 +820,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -1106,10 +1106,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestXmlMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestXmlMessage ParseFrom(pb::CodedInputStream input) {
+    public static TestXmlMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestXmlMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestXmlMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1200,11 +1200,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1547,10 +1547,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestXmlExtension ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestXmlExtension ParseFrom(pb::CodedInputStream input) {
+    public static TestXmlExtension ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestXmlExtension ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestXmlExtension ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1619,11 +1619,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers/AbstractBuilder.cs b/src/ProtocolBuffers/AbstractBuilder.cs
index ae5b306385..ca7e364956 100644
--- a/src/ProtocolBuffers/AbstractBuilder.cs
+++ b/src/ProtocolBuffers/AbstractBuilder.cs
@@ -159,7 +159,7 @@ namespace Google.ProtocolBuffers
             return ThisBuilder;
         }
 
-        public override TBuilder MergeFrom(CodedInputStream input, ExtensionRegistry extensionRegistry)
+        public override TBuilder MergeFrom(ICodedInputStream input, ExtensionRegistry extensionRegistry)
         {
             UnknownFieldSet.Builder unknownFields = UnknownFieldSet.CreateBuilder(UnknownFields);
             unknownFields.MergeFrom(input, extensionRegistry, this);
@@ -209,12 +209,12 @@ namespace Google.ProtocolBuffers
             return MergeFrom(message);
         }
 
-        IBuilder IBuilder.WeakMergeFrom(CodedInputStream input)
+        IBuilder IBuilder.WeakMergeFrom(ICodedInputStream input)
         {
             return MergeFrom(input);
         }
 
-        IBuilder IBuilder.WeakMergeFrom(CodedInputStream input, ExtensionRegistry registry)
+        IBuilder IBuilder.WeakMergeFrom(ICodedInputStream input, ExtensionRegistry registry)
         {
             return MergeFrom(input, registry);
         }
diff --git a/src/ProtocolBuffers/AbstractBuilderLite.cs b/src/ProtocolBuffers/AbstractBuilderLite.cs
index 756f621e6c..8ab0ca970b 100644
--- a/src/ProtocolBuffers/AbstractBuilderLite.cs
+++ b/src/ProtocolBuffers/AbstractBuilderLite.cs
@@ -62,13 +62,13 @@ namespace Google.ProtocolBuffers
 
         public abstract TBuilder MergeFrom(IMessageLite other);
 
-        public abstract TBuilder MergeFrom(CodedInputStream input, ExtensionRegistry extensionRegistry);
+        public abstract TBuilder MergeFrom(ICodedInputStream input, ExtensionRegistry extensionRegistry);
 
         public abstract TMessage DefaultInstanceForType { get; }
 
         #region IBuilderLite<TMessage,TBuilder> Members
 
-        public virtual TBuilder MergeFrom(CodedInputStream input)
+        public virtual TBuilder MergeFrom(ICodedInputStream input)
         {
             return MergeFrom(input, ExtensionRegistry.CreateInstance());
         }
@@ -154,12 +154,12 @@ namespace Google.ProtocolBuffers
             return MergeFrom(data, registry);
         }
 
-        IBuilderLite IBuilderLite.WeakMergeFrom(CodedInputStream input)
+        IBuilderLite IBuilderLite.WeakMergeFrom(ICodedInputStream input)
         {
             return MergeFrom(input);
         }
 
-        IBuilderLite IBuilderLite.WeakMergeFrom(CodedInputStream input, ExtensionRegistry registry)
+        IBuilderLite IBuilderLite.WeakMergeFrom(ICodedInputStream input, ExtensionRegistry registry)
         {
             return MergeFrom(input, registry);
         }
diff --git a/src/ProtocolBuffers/CodedInputStream.cs b/src/ProtocolBuffers/CodedInputStream.cs
index 92e547fcee..74fa94758f 100644
--- a/src/ProtocolBuffers/CodedInputStream.cs
+++ b/src/ProtocolBuffers/CodedInputStream.cs
@@ -58,7 +58,7 @@ namespace Google.ProtocolBuffers
     /// TODO(jonskeet): Consider whether recursion and size limits shouldn't be readonly,
     /// set at construction time.
     /// </remarks>
-    public sealed partial class CodedInputStream
+    public sealed partial class CodedInputStream : ICodedInputStream
     {
         private readonly byte[] buffer;
         private int bufferSize;
diff --git a/src/ProtocolBuffers/DescriptorProtos/CSharpOptions.cs b/src/ProtocolBuffers/DescriptorProtos/CSharpOptions.cs
index 5dbab8c8e0..a27e190468 100644
--- a/src/ProtocolBuffers/DescriptorProtos/CSharpOptions.cs
+++ b/src/ProtocolBuffers/DescriptorProtos/CSharpOptions.cs
@@ -400,10 +400,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static CSharpFileOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static CSharpFileOptions ParseFrom(pb::CodedInputStream input) {
+    public static CSharpFileOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static CSharpFileOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static CSharpFileOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -508,11 +508,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -937,10 +937,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static CSharpFieldOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static CSharpFieldOptions ParseFrom(pb::CodedInputStream input) {
+    public static CSharpFieldOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static CSharpFieldOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static CSharpFieldOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1009,11 +1009,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1162,10 +1162,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static CSharpServiceOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static CSharpServiceOptions ParseFrom(pb::CodedInputStream input) {
+    public static CSharpServiceOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static CSharpServiceOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static CSharpServiceOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1234,11 +1234,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1387,10 +1387,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static CSharpMethodOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static CSharpMethodOptions ParseFrom(pb::CodedInputStream input) {
+    public static CSharpMethodOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static CSharpMethodOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static CSharpMethodOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1459,11 +1459,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs b/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs
index 365a0449fb..3bacc235ba 100644
--- a/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs
+++ b/src/ProtocolBuffers/DescriptorProtos/DescriptorProtoFile.cs
@@ -321,10 +321,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static FileDescriptorSet ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static FileDescriptorSet ParseFrom(pb::CodedInputStream input) {
+    public static FileDescriptorSet ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static FileDescriptorSet ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static FileDescriptorSet ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -394,11 +394,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -708,10 +708,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static FileDescriptorProto ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static FileDescriptorProto ParseFrom(pb::CodedInputStream input) {
+    public static FileDescriptorProto ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static FileDescriptorProto ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static FileDescriptorProto ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -806,11 +806,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -1273,10 +1273,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         public static ExtensionRange ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static ExtensionRange ParseFrom(pb::CodedInputStream input) {
+        public static ExtensionRange ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static ExtensionRange ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static ExtensionRange ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1348,11 +1348,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -1621,10 +1621,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static DescriptorProto ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static DescriptorProto ParseFrom(pb::CodedInputStream input) {
+    public static DescriptorProto ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static DescriptorProto ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static DescriptorProto ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1716,11 +1716,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -2278,10 +2278,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static FieldDescriptorProto ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static FieldDescriptorProto ParseFrom(pb::CodedInputStream input) {
+    public static FieldDescriptorProto ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static FieldDescriptorProto ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static FieldDescriptorProto ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -2371,11 +2371,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -2760,10 +2760,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static EnumDescriptorProto ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static EnumDescriptorProto ParseFrom(pb::CodedInputStream input) {
+    public static EnumDescriptorProto ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static EnumDescriptorProto ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static EnumDescriptorProto ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -2839,11 +2839,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -3114,10 +3114,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static EnumValueDescriptorProto ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static EnumValueDescriptorProto ParseFrom(pb::CodedInputStream input) {
+    public static EnumValueDescriptorProto ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static EnumValueDescriptorProto ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static EnumValueDescriptorProto ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3192,11 +3192,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -3452,10 +3452,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static ServiceDescriptorProto ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ServiceDescriptorProto ParseFrom(pb::CodedInputStream input) {
+    public static ServiceDescriptorProto ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ServiceDescriptorProto ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ServiceDescriptorProto ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3531,11 +3531,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -3822,10 +3822,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static MethodDescriptorProto ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static MethodDescriptorProto ParseFrom(pb::CodedInputStream input) {
+    public static MethodDescriptorProto ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static MethodDescriptorProto ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static MethodDescriptorProto ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3903,11 +3903,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -4284,10 +4284,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static FileOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static FileOptions ParseFrom(pb::CodedInputStream input) {
+    public static FileOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static FileOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static FileOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -4379,11 +4379,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -4756,10 +4756,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static MessageOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static MessageOptions ParseFrom(pb::CodedInputStream input) {
+    public static MessageOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static MessageOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static MessageOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -4836,11 +4836,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5141,10 +5141,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static FieldOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static FieldOptions ParseFrom(pb::CodedInputStream input) {
+    public static FieldOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static FieldOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static FieldOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5227,11 +5227,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5505,10 +5505,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static EnumOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static EnumOptions ParseFrom(pb::CodedInputStream input) {
+    public static EnumOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static EnumOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static EnumOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5579,11 +5579,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5760,10 +5760,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static EnumValueOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static EnumValueOptions ParseFrom(pb::CodedInputStream input) {
+    public static EnumValueOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static EnumValueOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static EnumValueOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5834,11 +5834,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -6015,10 +6015,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static ServiceOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ServiceOptions ParseFrom(pb::CodedInputStream input) {
+    public static ServiceOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ServiceOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ServiceOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6089,11 +6089,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -6270,10 +6270,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static MethodOptions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static MethodOptions ParseFrom(pb::CodedInputStream input) {
+    public static MethodOptions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static MethodOptions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static MethodOptions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6344,11 +6344,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -6564,10 +6564,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         public static NamePart ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static NamePart ParseFrom(pb::CodedInputStream input) {
+        public static NamePart ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static NamePart ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static NamePart ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -6639,11 +6639,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -6878,10 +6878,10 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
     public static UninterpretedOption ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static UninterpretedOption ParseFrom(pb::CodedInputStream input) {
+    public static UninterpretedOption ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static UninterpretedOption ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static UninterpretedOption ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6966,11 +6966,11 @@ namespace Google.ProtocolBuffers.DescriptorProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffers/DynamicMessage.cs b/src/ProtocolBuffers/DynamicMessage.cs
index 3103706ca8..cd874a70f4 100644
--- a/src/ProtocolBuffers/DynamicMessage.cs
+++ b/src/ProtocolBuffers/DynamicMessage.cs
@@ -395,7 +395,7 @@ namespace Google.ProtocolBuffers
                 get { return fields.IsInitializedWithRespectTo(type.Fields); }
             }
 
-            public override Builder MergeFrom(CodedInputStream input, ExtensionRegistry extensionRegistry)
+            public override Builder MergeFrom(ICodedInputStream input, ExtensionRegistry extensionRegistry)
             {
                 UnknownFieldSet.Builder unknownFieldsBuilder = UnknownFieldSet.CreateBuilder(unknownFields);
                 unknownFieldsBuilder.MergeFrom(input, extensionRegistry, this);
diff --git a/src/ProtocolBuffers/ExtendableBuilder.cs b/src/ProtocolBuffers/ExtendableBuilder.cs
index 49265f4bf9..cbe203dd81 100644
--- a/src/ProtocolBuffers/ExtendableBuilder.cs
+++ b/src/ProtocolBuffers/ExtendableBuilder.cs
@@ -130,7 +130,7 @@ namespace Google.ProtocolBuffers
         /// </summary>
         /// <returns>true unless the tag is an end-group tag</returns>
         [CLSCompliant(false)]
-        protected override bool ParseUnknownField(CodedInputStream input, UnknownFieldSet.Builder unknownFields,
+        protected override bool ParseUnknownField(ICodedInputStream input, UnknownFieldSet.Builder unknownFields,
                                                   ExtensionRegistry extensionRegistry, uint tag, string fieldName)
         {
             return unknownFields.MergeFieldFrom(input, extensionRegistry, this, tag, fieldName);
diff --git a/src/ProtocolBuffers/ExtendableBuilderLite.cs b/src/ProtocolBuffers/ExtendableBuilderLite.cs
index f9508d4a38..bac82bcb21 100644
--- a/src/ProtocolBuffers/ExtendableBuilderLite.cs
+++ b/src/ProtocolBuffers/ExtendableBuilderLite.cs
@@ -133,7 +133,7 @@ namespace Google.ProtocolBuffers
         /// </summary>
         /// <returns>true unless the tag is an end-group tag</returns>
         [CLSCompliant(false)]
-        protected override bool ParseUnknownField(CodedInputStream input,
+        protected override bool ParseUnknownField(ICodedInputStream input,
                                                   ExtensionRegistry extensionRegistry, uint tag, string fieldName)
         {
             FieldSet extensions = MessageBeingBuilt.Extensions;
diff --git a/src/ProtocolBuffers/GeneratedBuilder.cs b/src/ProtocolBuffers/GeneratedBuilder.cs
index 699320abaa..4d4be2112a 100644
--- a/src/ProtocolBuffers/GeneratedBuilder.cs
+++ b/src/ProtocolBuffers/GeneratedBuilder.cs
@@ -115,7 +115,7 @@ namespace Google.ProtocolBuffers
         /// </summary>
         /// <returns>true unless the tag is an end-group tag</returns>
         [CLSCompliant(false)]
-        protected virtual bool ParseUnknownField(CodedInputStream input, UnknownFieldSet.Builder unknownFields,
+        protected virtual bool ParseUnknownField(ICodedInputStream input, UnknownFieldSet.Builder unknownFields,
                                                  ExtensionRegistry extensionRegistry, uint tag, string fieldName)
         {
             return unknownFields.MergeFieldFrom(tag, input);
diff --git a/src/ProtocolBuffers/GeneratedBuilderLite.cs b/src/ProtocolBuffers/GeneratedBuilderLite.cs
index 2562842269..b916a8b0ec 100644
--- a/src/ProtocolBuffers/GeneratedBuilderLite.cs
+++ b/src/ProtocolBuffers/GeneratedBuilderLite.cs
@@ -98,7 +98,7 @@ namespace Google.ProtocolBuffers
         /// </summary>
         /// <returns>true unless the tag is an end-group tag</returns>
         [CLSCompliant(false)]
-        protected virtual bool ParseUnknownField(CodedInputStream input,
+        protected virtual bool ParseUnknownField(ICodedInputStream input,
                                                  ExtensionRegistry extensionRegistry, uint tag, string fieldName)
         {
             return input.SkipField();
diff --git a/src/ProtocolBuffers/IBuilder.cs b/src/ProtocolBuffers/IBuilder.cs
index 7a9d690720..f9c0df619c 100644
--- a/src/ProtocolBuffers/IBuilder.cs
+++ b/src/ProtocolBuffers/IBuilder.cs
@@ -128,8 +128,8 @@ namespace Google.ProtocolBuffers
         IBuilder WeakMergeFrom(IMessage message);
         new IBuilder WeakMergeFrom(ByteString data);
         new IBuilder WeakMergeFrom(ByteString data, ExtensionRegistry registry);
-        new IBuilder WeakMergeFrom(CodedInputStream input);
-        new IBuilder WeakMergeFrom(CodedInputStream input, ExtensionRegistry registry);
+        new IBuilder WeakMergeFrom(ICodedInputStream input);
+        new IBuilder WeakMergeFrom(ICodedInputStream input, ExtensionRegistry registry);
         new IMessage WeakBuild();
         new IMessage WeakBuildPartial();
         new IBuilder WeakClone();
@@ -203,15 +203,15 @@ namespace Google.ProtocolBuffers
         /// Use BuildPartial to build, which ignores missing required fields.
         /// </list>
         /// </remarks>
-        new TBuilder MergeFrom(CodedInputStream input);
+        new TBuilder MergeFrom(ICodedInputStream input);
 
         /// <summary>
-        /// Like MergeFrom(CodedInputStream), but also parses extensions.
+        /// Like MergeFrom(ICodedInputStream), but also parses extensions.
         /// The extensions that you want to be able to parse must be registered
         /// in <paramref name="extensionRegistry"/>. Extensions not in the registry
         /// will be treated as unknown fields.
         /// </summary>
-        new TBuilder MergeFrom(CodedInputStream input, ExtensionRegistry extensionRegistry);
+        new TBuilder MergeFrom(ICodedInputStream input, ExtensionRegistry extensionRegistry);
 
         /// <summary>
         /// Get's the message's type's default instance.
@@ -260,35 +260,35 @@ namespace Google.ProtocolBuffers
         /// <summary>
         /// Parse <paramref name="data"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream).
+        /// MergeFrom(ICodedInputStream).
         /// </summary>
         new TBuilder MergeFrom(ByteString data);
 
         /// <summary>
         /// Parse <paramref name="data"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream, extensionRegistry).
+        /// MergeFrom(ICodedInputStream, extensionRegistry).
         /// </summary>
         new TBuilder MergeFrom(ByteString data, ExtensionRegistry extensionRegistry);
 
         /// <summary>
         /// Parse <paramref name="data"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream).
+        /// MergeFrom(ICodedInputStream).
         /// </summary>
         new TBuilder MergeFrom(byte[] data);
 
         /// <summary>
         /// Parse <paramref name="data"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream, extensionRegistry).
+        /// MergeFrom(ICodedInputStream, extensionRegistry).
         /// </summary>
         new TBuilder MergeFrom(byte[] data, ExtensionRegistry extensionRegistry);
 
         /// <summary>
         /// Parse <paramref name="input"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream). Note that this method always reads
+        /// MergeFrom(ICodedInputStream). Note that this method always reads
         /// the entire input (unless it throws an exception). If you want it to
         /// stop earlier, you will need to wrap the input in a wrapper
         /// stream which limits reading. Or, use IMessage.WriteDelimitedTo(Stream)
@@ -300,7 +300,7 @@ namespace Google.ProtocolBuffers
         /// <summary>
         /// Parse <paramref name="input"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream, extensionRegistry).
+        /// MergeFrom(ICodedInputStream, extensionRegistry).
         /// </summary>
         new TBuilder MergeFrom(Stream input, ExtensionRegistry extensionRegistry);
 
diff --git a/src/ProtocolBuffers/IBuilderLite.cs b/src/ProtocolBuffers/IBuilderLite.cs
index 6cc14d6c0a..3cef895c51 100644
--- a/src/ProtocolBuffers/IBuilderLite.cs
+++ b/src/ProtocolBuffers/IBuilderLite.cs
@@ -60,8 +60,8 @@ namespace Google.ProtocolBuffers
         IBuilderLite WeakMergeFrom(IMessageLite message);
         IBuilderLite WeakMergeFrom(ByteString data);
         IBuilderLite WeakMergeFrom(ByteString data, ExtensionRegistry registry);
-        IBuilderLite WeakMergeFrom(CodedInputStream input);
-        IBuilderLite WeakMergeFrom(CodedInputStream input, ExtensionRegistry registry);
+        IBuilderLite WeakMergeFrom(ICodedInputStream input);
+        IBuilderLite WeakMergeFrom(ICodedInputStream input, ExtensionRegistry registry);
         IMessageLite WeakBuild();
         IMessageLite WeakBuildPartial();
         IBuilderLite WeakClone();
@@ -131,15 +131,15 @@ namespace Google.ProtocolBuffers
         /// Use BuildPartial to build, which ignores missing required fields.
         /// </list>
         /// </remarks>
-        TBuilder MergeFrom(CodedInputStream input);
+        TBuilder MergeFrom(ICodedInputStream input);
 
         /// <summary>
-        /// Like MergeFrom(CodedInputStream), but also parses extensions.
+        /// Like MergeFrom(ICodedInputStream), but also parses extensions.
         /// The extensions that you want to be able to parse must be registered
         /// in <paramref name="extensionRegistry"/>. Extensions not in the registry
         /// will be treated as unknown fields.
         /// </summary>
-        TBuilder MergeFrom(CodedInputStream input, ExtensionRegistry extensionRegistry);
+        TBuilder MergeFrom(ICodedInputStream input, ExtensionRegistry extensionRegistry);
 
         /// <summary>
         /// Get's the message's type's default instance.
@@ -166,35 +166,35 @@ namespace Google.ProtocolBuffers
         /// <summary>
         /// Parse <paramref name="data"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream).
+        /// MergeFrom(ICodedInputStream).
         /// </summary>
         TBuilder MergeFrom(ByteString data);
 
         /// <summary>
         /// Parse <paramref name="data"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream, ExtensionRegistry).
+        /// MergeFrom(ICodedInputStream, ExtensionRegistry).
         /// </summary>
         TBuilder MergeFrom(ByteString data, ExtensionRegistry extensionRegistry);
 
         /// <summary>
         /// Parse <paramref name="data"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream).
+        /// MergeFrom(ICodedInputStream).
         /// </summary>
         TBuilder MergeFrom(byte[] data);
 
         /// <summary>
         /// Parse <paramref name="data"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream, ExtensionRegistry).
+        /// MergeFrom(ICodedInputStream, ExtensionRegistry).
         /// </summary>
         TBuilder MergeFrom(byte[] data, ExtensionRegistry extensionRegistry);
 
         /// <summary>
         /// Parse <paramref name="input"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream). Note that this method always reads
+        /// MergeFrom(ICodedInputStream). Note that this method always reads
         /// the entire input (unless it throws an exception). If you want it to
         /// stop earlier, you will need to wrap the input in a wrapper
         /// stream which limits reading. Or, use IMessage.WriteDelimitedTo(Stream)
@@ -206,7 +206,7 @@ namespace Google.ProtocolBuffers
         /// <summary>
         /// Parse <paramref name="input"/> as a message of this type and merge
         /// it with the message being built. This is just a small wrapper around
-        /// MergeFrom(CodedInputStream, ExtensionRegistry).
+        /// MergeFrom(ICodedInputStream, ExtensionRegistry).
         /// </summary>
         TBuilder MergeFrom(Stream input, ExtensionRegistry extensionRegistry);
 
diff --git a/src/ProtocolBuffers/ICodedInputStream.cs b/src/ProtocolBuffers/ICodedInputStream.cs
new file mode 100644
index 0000000000..f385454b0c
--- /dev/null
+++ b/src/ProtocolBuffers/ICodedInputStream.cs
@@ -0,0 +1,198 @@
+using System;
+using System.Collections.Generic;
+using Google.ProtocolBuffers.Descriptors;
+
+//Disable warning CS3010: CLS-compliant interfaces must have only CLS-compliant members
+#pragma warning disable 3010
+
+namespace Google.ProtocolBuffers
+{
+    public interface ICodedInputStream
+    {
+        /// <summary>
+        /// Attempt to read a field tag, returning false if we have reached the end
+        /// of the input data.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// If fieldTag is non-zero and ReadTag returns true then the value in fieldName
+        /// may or may not be populated.  However, if fieldTag is zero and ReadTag returns
+        /// true, then fieldName should be populated with a non-null field name.
+        /// </para><para>
+        /// In other words if ReadTag returns true then either fieldTag will be non-zero OR
+        /// fieldName will be non-zero.  In some cases both may be populated, however the
+        /// builders will always prefer the fieldTag over fieldName.
+        /// </para>
+        /// </remarks>
+        [CLSCompliant(false)]
+        bool ReadTag(out uint fieldTag, out string fieldName);
+
+        /// <summary>
+        /// Read a double field from the stream.
+        /// </summary>
+        bool ReadDouble(ref double value);
+
+        /// <summary>
+        /// Read a float field from the stream.
+        /// </summary>
+        bool ReadFloat(ref float value);
+
+        /// <summary>
+        /// Read a uint64 field from the stream.
+        /// </summary>
+        [CLSCompliant(false)]
+        bool ReadUInt64(ref ulong value);
+
+        /// <summary>
+        /// Read an int64 field from the stream.
+        /// </summary>
+        bool ReadInt64(ref long value);
+
+        /// <summary>
+        /// Read an int32 field from the stream.
+        /// </summary>
+        bool ReadInt32(ref int value);
+
+        /// <summary>
+        /// Read a fixed64 field from the stream.
+        /// </summary>
+        [CLSCompliant(false)]
+        bool ReadFixed64(ref ulong value);
+
+        /// <summary>
+        /// Read a fixed32 field from the stream.
+        /// </summary>
+        [CLSCompliant(false)]
+        bool ReadFixed32(ref uint value);
+
+        /// <summary>
+        /// Read a bool field from the stream.
+        /// </summary>
+        bool ReadBool(ref bool value);
+
+        /// <summary>
+        /// Reads a string field from the stream.
+        /// </summary>
+        bool ReadString(ref string value);
+
+        /// <summary>
+        /// Reads a group field value from the stream.
+        /// </summary>    
+        void ReadGroup(int fieldNumber, IBuilderLite builder,
+                                       ExtensionRegistry extensionRegistry);
+
+        /// <summary>
+        /// Reads a group field value from the stream and merges it into the given
+        /// UnknownFieldSet.
+        /// </summary>   
+        [Obsolete]
+        void ReadUnknownGroup(int fieldNumber, IBuilderLite builder);
+
+        /// <summary>
+        /// Reads an embedded message field value from the stream.
+        /// </summary>   
+        void ReadMessage(IBuilderLite builder, ExtensionRegistry extensionRegistry);
+
+        /// <summary>
+        /// Reads a bytes field value from the stream.
+        /// </summary>   
+        bool ReadBytes(ref ByteString value);
+
+        /// <summary>
+        /// Reads a uint32 field value from the stream.
+        /// </summary>   
+        [CLSCompliant(false)]
+        bool ReadUInt32(ref uint value);
+
+        /// <summary>
+        /// Reads an enum field value from the stream. The caller is responsible
+        /// for converting the numeric value to an actual enum.
+        /// </summary>   
+        bool ReadEnum(ref IEnumLite value, out object unknown, IEnumLiteMap mapping);
+
+        /// <summary>
+        /// Reads an enum field value from the stream. If the enum is valid for type T,
+        /// then the ref value is set and it returns true.  Otherwise the unkown output
+        /// value is set and this method returns false.
+        /// </summary>   
+        [CLSCompliant(false)]
+        bool ReadEnum<T>(ref T value, out object unknown)
+            where T : struct, IComparable, IFormattable, IConvertible;
+
+        /// <summary>
+        /// Reads an sfixed32 field value from the stream.
+        /// </summary>   
+        bool ReadSFixed32(ref int value);
+
+        /// <summary>
+        /// Reads an sfixed64 field value from the stream.
+        /// </summary>   
+        bool ReadSFixed64(ref long value);
+
+        /// <summary>
+        /// Reads an sint32 field value from the stream.
+        /// </summary>   
+        bool ReadSInt32(ref int value);
+
+        /// <summary>
+        /// Reads an sint64 field value from the stream.
+        /// </summary>   
+        bool ReadSInt64(ref long value);
+
+        /// <summary>
+        /// Reads an array of primitive values into the list, if the wire-type of fieldTag is length-prefixed and the 
+        /// type is numberic, it will read a packed array.
+        /// </summary>
+        [CLSCompliant(false)]
+        void ReadPrimitiveArray<T>(FieldType fieldType, uint fieldTag, string fieldName, ICollection<T> list);
+
+        /// <summary>
+        /// Reads an array of primitive values into the list, if the wire-type of fieldTag is length-prefixed, it will
+        /// read a packed array.
+        /// </summary>
+        [CLSCompliant(false)]
+        void ReadEnumArray(uint fieldTag, string fieldName, ICollection<IEnumLite> list, out ICollection<object> unknown, IEnumLiteMap mapping);
+
+        /// <summary>
+        /// Reads an array of primitive values into the list, if the wire-type of fieldTag is length-prefixed, it will
+        /// read a packed array.
+        /// </summary>
+        [CLSCompliant(false)]
+        void ReadEnumArray<T>(uint fieldTag, string fieldName, ICollection<T> list, out ICollection<object> unknown)
+            where T : struct, IComparable, IFormattable, IConvertible;
+
+        /// <summary>
+        /// Reads a set of messages using the <paramref name="messageType"/> as a template.  T is not guaranteed to be 
+        /// the most derived type, it is only the type specifier for the collection.
+        /// </summary>
+        [CLSCompliant(false)]
+        void ReadMessageArray<T>(uint fieldTag, string fieldName, ICollection<T> list, T messageType, ExtensionRegistry registry) where T : IMessageLite;
+
+        /// <summary>
+        /// Reads a set of messages using the <paramref name="messageType"/> as a template.
+        /// </summary>
+        [CLSCompliant(false)]
+        void ReadGroupArray<T>(uint fieldTag, string fieldName, ICollection<T> list, T messageType, ExtensionRegistry registry) where T : IMessageLite;
+
+        /// <summary>
+        /// Reads a field of any primitive type. Enums, groups and embedded
+        /// messages are not handled by this method.
+        /// </summary>
+        bool ReadPrimitiveField(FieldType fieldType, ref object value);
+
+        /// <summary>
+        /// Returns true if the stream has reached the end of the input. This is the
+        /// case if either the end of the underlying input source has been reached or
+        /// the stream has reached a limit created using PushLimit.
+        /// </summary>
+        bool IsAtEnd { get; }
+
+        /// <summary>
+        /// Reads and discards a single field, given its tag value.
+        /// </summary>
+        /// <returns>false if the tag is an end-group tag, in which case
+        /// nothing is skipped. Otherwise, returns true.</returns>
+        [CLSCompliant(false)]
+        bool SkipField();
+    }
+}
\ No newline at end of file
diff --git a/src/ProtocolBuffers/ProtocolBuffers.csproj b/src/ProtocolBuffers/ProtocolBuffers.csproj
index 5928cac41c..a059ca39fd 100644
--- a/src/ProtocolBuffers/ProtocolBuffers.csproj
+++ b/src/ProtocolBuffers/ProtocolBuffers.csproj
@@ -164,6 +164,7 @@
     <Compile Include="IBuilderLite.cs">
       <SubType>Code</SubType>
     </Compile>
+    <Compile Include="ICodedInputStream.cs" />
     <Compile Include="ICodedOutputStream.cs" />
     <Compile Include="IMessage.cs" />
     <Compile Include="IMessageLite.cs" />
diff --git a/src/ProtocolBuffers/ProtocolBuffersLite.csproj b/src/ProtocolBuffers/ProtocolBuffersLite.csproj
index 042ffd1738..936a6950f9 100644
--- a/src/ProtocolBuffers/ProtocolBuffersLite.csproj
+++ b/src/ProtocolBuffers/ProtocolBuffersLite.csproj
@@ -95,6 +95,7 @@
     <Compile Include="GeneratedBuilderLite.cs" />
     <Compile Include="GeneratedExtensionLite.cs" />
     <Compile Include="GeneratedMessageLite.cs" />
+    <Compile Include="ICodedInputStream.cs" />
     <Compile Include="ICodedOutputStream.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ByteString.cs" />
diff --git a/src/ProtocolBuffers/UnknownFieldSet.cs b/src/ProtocolBuffers/UnknownFieldSet.cs
index e0f1cfff04..13a295818c 100644
--- a/src/ProtocolBuffers/UnknownFieldSet.cs
+++ b/src/ProtocolBuffers/UnknownFieldSet.cs
@@ -251,7 +251,7 @@ namespace Google.ProtocolBuffers
         /// <summary>
         /// Parses an UnknownFieldSet from the given input.
         /// </summary>
-        public static UnknownFieldSet ParseFrom(CodedInputStream input)
+        public static UnknownFieldSet ParseFrom(ICodedInputStream input)
         {
             return CreateBuilder().MergeFrom(input).Build();
         }
@@ -417,7 +417,7 @@ namespace Google.ProtocolBuffers
             /// Parse an entire message from <paramref name="input"/> and merge
             /// its fields into this set.
             /// </summary>
-            public Builder MergeFrom(CodedInputStream input)
+            public Builder MergeFrom(ICodedInputStream input)
             {
                 uint tag;
                 string name;
@@ -444,7 +444,7 @@ namespace Google.ProtocolBuffers
             /// <param name="input">The coded input stream containing the field</param>
             /// <returns>false if the tag is an "end group" tag, true otherwise</returns>
             [CLSCompliant(false)]
-            public bool MergeFieldFrom(uint tag, CodedInputStream input)
+            public bool MergeFieldFrom(uint tag, ICodedInputStream input)
             {
                 int number = WireFormat.GetTagFieldNumber(tag);
                 switch (WireFormat.GetTagWireType(tag))
@@ -496,7 +496,7 @@ namespace Google.ProtocolBuffers
             /// <summary>
             /// Parses <paramref name="input"/> as an UnknownFieldSet and merge it
             /// with the set being built. This is just a small wrapper around
-            /// MergeFrom(CodedInputStream).
+            /// MergeFrom(ICodedInputStream).
             /// </summary>
             public Builder MergeFrom(Stream input)
             {
@@ -509,7 +509,7 @@ namespace Google.ProtocolBuffers
             /// <summary>
             /// Parses <paramref name="data"/> as an UnknownFieldSet and merge it
             /// with the set being built. This is just a small wrapper around
-            /// MergeFrom(CodedInputStream).
+            /// MergeFrom(ICodedInputStream).
             /// </summary>
             public Builder MergeFrom(ByteString data)
             {
@@ -522,7 +522,7 @@ namespace Google.ProtocolBuffers
             /// <summary>
             /// Parses <paramref name="data"/> as an UnknownFieldSet and merge it
             /// with the set being built. This is just a small wrapper around
-            /// MergeFrom(CodedInputStream).
+            /// MergeFrom(ICodedInputStream).
             /// </summary>
             public Builder MergeFrom(byte[] data)
             {
@@ -601,7 +601,7 @@ namespace Google.ProtocolBuffers
                 return this;
             }
 
-            internal void MergeFrom(CodedInputStream input, ExtensionRegistry extensionRegistry, IBuilder builder)
+            internal void MergeFrom(ICodedInputStream input, ExtensionRegistry extensionRegistry, IBuilder builder)
             {
                 uint tag;
                 string name;
@@ -623,7 +623,7 @@ namespace Google.ProtocolBuffers
             }
 
             /// <summary>
-            /// Like <see cref="MergeFrom(CodedInputStream, ExtensionRegistry, IBuilder)" />
+            /// Like <see cref="MergeFrom(ICodedInputStream, ExtensionRegistry, IBuilder)" />
             /// but parses a single field.
             /// </summary>
             /// <param name="input">The input to read the field from</param>
@@ -631,7 +631,7 @@ namespace Google.ProtocolBuffers
             /// <param name="builder">Builder to merge field into, if it's a known field</param>
             /// <param name="tag">The tag, which should already have been read from the input</param>
             /// <returns>true unless the tag is an end-group tag</returns>
-            internal bool MergeFieldFrom(CodedInputStream input,
+            internal bool MergeFieldFrom(ICodedInputStream input,
                                          ExtensionRegistry extensionRegistry, IBuilder builder, uint tag, string fieldName)
             {
                 MessageDescriptor type = builder.DescriptorForType;
@@ -753,7 +753,7 @@ namespace Google.ProtocolBuffers
             /// <summary>
             /// Called by MergeFieldFrom to parse a MessageSet extension.
             /// </summary>
-            private void MergeMessageSetExtensionFromCodedStream(CodedInputStream input,
+            private void MergeMessageSetExtensionFromCodedStream(ICodedInputStream input,
                                                                  ExtensionRegistry extensionRegistry, IBuilder builder)
             {
                 MessageDescriptor type = builder.DescriptorForType;
@@ -779,6 +779,7 @@ namespace Google.ProtocolBuffers
                 IBuilderLite subBuilder = null;
                 FieldDescriptor field = null;
 
+                uint lastTag = WireFormat.MessageSetTag.ItemStart;
                 uint tag;
                 string name;
                 while (input.ReadTag(out tag, out name))
@@ -790,6 +791,7 @@ namespace Google.ProtocolBuffers
                         break;
                     }
 
+                    lastTag = tag;
                     if (tag == WireFormat.MessageSetTag.TypeID)
                     {
                         typeId = 0;
@@ -855,7 +857,8 @@ namespace Google.ProtocolBuffers
                     }
                 }
 
-                input.CheckLastTagWas(WireFormat.MessageSetTag.ItemEnd);
+                if (lastTag != WireFormat.MessageSetTag.ItemEnd)
+                    throw InvalidProtocolBufferException.InvalidEndTag();
 
                 if (subBuilder != null)
                 {
@@ -890,12 +893,12 @@ namespace Google.ProtocolBuffers
                 return MergeFrom(data);
             }
 
-            IBuilderLite IBuilderLite.WeakMergeFrom(CodedInputStream input)
+            IBuilderLite IBuilderLite.WeakMergeFrom(ICodedInputStream input)
             {
                 return MergeFrom(input);
             }
 
-            IBuilderLite IBuilderLite.WeakMergeFrom(CodedInputStream input, ExtensionRegistry registry)
+            IBuilderLite IBuilderLite.WeakMergeFrom(ICodedInputStream input, ExtensionRegistry registry)
             {
                 return MergeFrom(input);
             }
diff --git a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestExtrasFullProtoFile.cs b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestExtrasFullProtoFile.cs
index 266b4f10f0..04a46dfec2 100644
--- a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestExtrasFullProtoFile.cs
+++ b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestExtrasFullProtoFile.cs
@@ -229,10 +229,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static PhoneNumber ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static PhoneNumber ParseFrom(pb::CodedInputStream input) {
+        public static PhoneNumber ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static PhoneNumber ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static PhoneNumber ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -426,10 +426,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Addresses ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Addresses ParseFrom(pb::CodedInputStream input) {
+        public static Addresses ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Addresses ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Addresses ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -675,10 +675,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestInteropPerson ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestInteropPerson ParseFrom(pb::CodedInputStream input) {
+    public static TestInteropPerson ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestInteropPerson ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestInteropPerson ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -955,10 +955,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestInteropEmployeeId ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestInteropEmployeeId ParseFrom(pb::CodedInputStream input) {
+    public static TestInteropEmployeeId ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestInteropEmployeeId ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestInteropEmployeeId ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1135,10 +1135,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static SubA ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static SubA ParseFrom(pb::CodedInputStream input) {
+        public static SubA ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static SubA ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static SubA ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1309,10 +1309,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMissingFieldsA ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMissingFieldsA ParseFrom(pb::CodedInputStream input) {
+    public static TestMissingFieldsA ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMissingFieldsA ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMissingFieldsA ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1552,10 +1552,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static SubB ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static SubB ParseFrom(pb::CodedInputStream input) {
+        public static SubB ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static SubB ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static SubB ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1708,10 +1708,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMissingFieldsB ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMissingFieldsB ParseFrom(pb::CodedInputStream input) {
+    public static TestMissingFieldsB ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMissingFieldsB ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMissingFieldsB ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
diff --git a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestExtrasLiteProtoFile.cs b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestExtrasLiteProtoFile.cs
index abe47a2c80..af53cc0806 100644
--- a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestExtrasLiteProtoFile.cs
+++ b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestExtrasLiteProtoFile.cs
@@ -172,10 +172,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRequiredLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRequiredLite ParseFrom(pb::CodedInputStream input) {
+    public static TestRequiredLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRequiredLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRequiredLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -242,11 +242,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -469,10 +469,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static PhoneNumber ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static PhoneNumber ParseFrom(pb::CodedInputStream input) {
+        public static PhoneNumber ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static PhoneNumber ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static PhoneNumber ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -539,11 +539,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             uint tag;
             string field_name;
             while (input.ReadTag(out tag, out field_name)) {
@@ -798,10 +798,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Addresses ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Addresses ParseFrom(pb::CodedInputStream input) {
+        public static Addresses ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Addresses ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Addresses ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -877,11 +877,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             uint tag;
             string field_name;
             while (input.ReadTag(out tag, out field_name)) {
@@ -1239,10 +1239,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestInteropPersonLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestInteropPersonLite ParseFrom(pb::CodedInputStream input) {
+    public static TestInteropPersonLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestInteropPersonLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestInteropPersonLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1325,11 +1325,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -1637,10 +1637,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestInteropEmployeeIdLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestInteropEmployeeIdLite ParseFrom(pb::CodedInputStream input) {
+    public static TestInteropEmployeeIdLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestInteropEmployeeIdLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestInteropEmployeeIdLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -1704,11 +1704,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
diff --git a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestImportLiteProtoFile.cs b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestImportLiteProtoFile.cs
index 0e890f3327..19d89891f9 100644
--- a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestImportLiteProtoFile.cs
+++ b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestImportLiteProtoFile.cs
@@ -135,10 +135,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ImportMessageLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ImportMessageLite ParseFrom(pb::CodedInputStream input) {
+    public static ImportMessageLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ImportMessageLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ImportMessageLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -202,11 +202,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
diff --git a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestImportProtoFile.cs b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestImportProtoFile.cs
index cbd6cea36c..7fd62591e9 100644
--- a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestImportProtoFile.cs
+++ b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestImportProtoFile.cs
@@ -154,10 +154,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ImportMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ImportMessage ParseFrom(pb::CodedInputStream input) {
+    public static ImportMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ImportMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ImportMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -226,11 +226,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
diff --git a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestLiteImportNonLiteProtoFile.cs b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestLiteImportNonLiteProtoFile.cs
index cc9778f376..cc0a4c015e 100644
--- a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestLiteImportNonLiteProtoFile.cs
+++ b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestLiteImportNonLiteProtoFile.cs
@@ -124,10 +124,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestLiteImportsNonlite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestLiteImportsNonlite ParseFrom(pb::CodedInputStream input) {
+    public static TestLiteImportsNonlite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestLiteImportsNonlite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestLiteImportsNonlite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -191,11 +191,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
diff --git a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestLiteProtoFile.cs b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestLiteProtoFile.cs
index c843f3f56b..8afb0d6ac7 100644
--- a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestLiteProtoFile.cs
+++ b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestLiteProtoFile.cs
@@ -1178,10 +1178,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static NestedMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1245,11 +1245,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             uint tag;
             string field_name;
             while (input.ReadTag(out tag, out field_name)) {
@@ -1396,10 +1396,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static OptionalGroup ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static OptionalGroup ParseFrom(pb::CodedInputStream input) {
+        public static OptionalGroup ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static OptionalGroup ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static OptionalGroup ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1463,11 +1463,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             uint tag;
             string field_name;
             while (input.ReadTag(out tag, out field_name)) {
@@ -1614,10 +1614,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static RepeatedGroup ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static RepeatedGroup ParseFrom(pb::CodedInputStream input) {
+        public static RepeatedGroup ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static RepeatedGroup ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static RepeatedGroup ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1681,11 +1681,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             uint tag;
             string field_name;
             while (input.ReadTag(out tag, out field_name)) {
@@ -3319,10 +3319,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestAllTypesLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestAllTypesLite ParseFrom(pb::CodedInputStream input) {
+    public static TestAllTypesLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestAllTypesLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestAllTypesLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3611,11 +3611,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -5647,10 +5647,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ForeignMessageLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ForeignMessageLite ParseFrom(pb::CodedInputStream input) {
+    public static ForeignMessageLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ForeignMessageLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ForeignMessageLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5714,11 +5714,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -6303,10 +6303,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestPackedTypesLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestPackedTypesLite ParseFrom(pb::CodedInputStream input) {
+    public static TestPackedTypesLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestPackedTypesLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestPackedTypesLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6423,11 +6423,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -6981,10 +6981,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestAllExtensionsLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestAllExtensionsLite ParseFrom(pb::CodedInputStream input) {
+    public static TestAllExtensionsLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestAllExtensionsLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestAllExtensionsLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -7046,11 +7046,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -7175,10 +7175,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static OptionalGroup_extension_lite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static OptionalGroup_extension_lite ParseFrom(pb::CodedInputStream input) {
+    public static OptionalGroup_extension_lite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static OptionalGroup_extension_lite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static OptionalGroup_extension_lite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -7242,11 +7242,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -7393,10 +7393,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static RepeatedGroup_extension_lite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static RepeatedGroup_extension_lite ParseFrom(pb::CodedInputStream input) {
+    public static RepeatedGroup_extension_lite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static RepeatedGroup_extension_lite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static RepeatedGroup_extension_lite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -7460,11 +7460,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -7599,10 +7599,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestPackedExtensionsLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestPackedExtensionsLite ParseFrom(pb::CodedInputStream input) {
+    public static TestPackedExtensionsLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestPackedExtensionsLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestPackedExtensionsLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -7664,11 +7664,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -7776,10 +7776,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestNestedExtensionLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestNestedExtensionLite ParseFrom(pb::CodedInputStream input) {
+    public static TestNestedExtensionLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestNestedExtensionLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestNestedExtensionLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -7840,11 +7840,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -7969,10 +7969,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestDeprecatedLite ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestDeprecatedLite ParseFrom(pb::CodedInputStream input) {
+    public static TestDeprecatedLite ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestDeprecatedLite ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestDeprecatedLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -8036,11 +8036,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
diff --git a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestProtoFile.cs b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestProtoFile.cs
index d564a02854..5da244d1e4 100644
--- a/src/ProtocolBuffersLite.Test/TestProtos/UnitTestProtoFile.cs
+++ b/src/ProtocolBuffersLite.Test/TestProtos/UnitTestProtoFile.cs
@@ -1151,10 +1151,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static NestedMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1223,11 +1223,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -1375,10 +1375,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static OptionalGroup ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static OptionalGroup ParseFrom(pb::CodedInputStream input) {
+        public static OptionalGroup ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static OptionalGroup ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static OptionalGroup ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1447,11 +1447,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -1599,10 +1599,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static RepeatedGroup ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static RepeatedGroup ParseFrom(pb::CodedInputStream input) {
+        public static RepeatedGroup ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static RepeatedGroup ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static RepeatedGroup ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -1671,11 +1671,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -3029,10 +3029,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestAllTypes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestAllTypes ParseFrom(pb::CodedInputStream input) {
+    public static TestAllTypes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestAllTypes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestAllTypes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -3326,11 +3326,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5411,10 +5411,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestDeprecatedFields ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestDeprecatedFields ParseFrom(pb::CodedInputStream input) {
+    public static TestDeprecatedFields ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestDeprecatedFields ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestDeprecatedFields ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5483,11 +5483,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5635,10 +5635,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ForeignMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static ForeignMessage ParseFrom(pb::CodedInputStream input) {
+    public static ForeignMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static ForeignMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static ForeignMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5707,11 +5707,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -5847,10 +5847,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestAllExtensions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestAllExtensions ParseFrom(pb::CodedInputStream input) {
+    public static TestAllExtensions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestAllExtensions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestAllExtensions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -5917,11 +5917,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -6047,10 +6047,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static OptionalGroup_extension ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static OptionalGroup_extension ParseFrom(pb::CodedInputStream input) {
+    public static OptionalGroup_extension ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static OptionalGroup_extension ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static OptionalGroup_extension ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6119,11 +6119,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -6271,10 +6271,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static RepeatedGroup_extension ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static RepeatedGroup_extension ParseFrom(pb::CodedInputStream input) {
+    public static RepeatedGroup_extension ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static RepeatedGroup_extension ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static RepeatedGroup_extension ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6343,11 +6343,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -6481,10 +6481,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestNestedExtension ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestNestedExtension ParseFrom(pb::CodedInputStream input) {
+    public static TestNestedExtension ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestNestedExtension ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestNestedExtension ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -6550,11 +6550,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -7199,10 +7199,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRequired ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRequired ParseFrom(pb::CodedInputStream input) {
+    public static TestRequired ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRequired ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRequired ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -7367,11 +7367,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -8263,10 +8263,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRequiredForeign ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRequiredForeign ParseFrom(pb::CodedInputStream input) {
+    public static TestRequiredForeign ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRequiredForeign ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRequiredForeign ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -8342,11 +8342,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -8581,10 +8581,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestForeignNested ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestForeignNested ParseFrom(pb::CodedInputStream input) {
+    public static TestForeignNested ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestForeignNested ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestForeignNested ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -8653,11 +8653,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -8812,10 +8812,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestEmptyMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestEmptyMessage ParseFrom(pb::CodedInputStream input) {
+    public static TestEmptyMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestEmptyMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestEmptyMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -8881,11 +8881,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -8999,10 +8999,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestEmptyMessageWithExtensions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestEmptyMessageWithExtensions ParseFrom(pb::CodedInputStream input) {
+    public static TestEmptyMessageWithExtensions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestEmptyMessageWithExtensions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestEmptyMessageWithExtensions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -9069,11 +9069,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -9189,10 +9189,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMultipleExtensionRanges ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMultipleExtensionRanges ParseFrom(pb::CodedInputStream input) {
+    public static TestMultipleExtensionRanges ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMultipleExtensionRanges ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMultipleExtensionRanges ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -9259,11 +9259,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -9405,10 +9405,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestReallyLargeTagNumber ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestReallyLargeTagNumber ParseFrom(pb::CodedInputStream input) {
+    public static TestReallyLargeTagNumber ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestReallyLargeTagNumber ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestReallyLargeTagNumber ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -9480,11 +9480,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -9670,10 +9670,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRecursiveMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRecursiveMessage ParseFrom(pb::CodedInputStream input) {
+    public static TestRecursiveMessage ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRecursiveMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRecursiveMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -9745,11 +9745,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -9942,10 +9942,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMutualRecursionA ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMutualRecursionA ParseFrom(pb::CodedInputStream input) {
+    public static TestMutualRecursionA ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMutualRecursionA ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMutualRecursionA ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -10014,11 +10014,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -10205,10 +10205,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestMutualRecursionB ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestMutualRecursionB ParseFrom(pb::CodedInputStream input) {
+    public static TestMutualRecursionB ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestMutualRecursionB ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestMutualRecursionB ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -10280,11 +10280,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -10507,10 +10507,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Foo ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Foo ParseFrom(pb::CodedInputStream input) {
+        public static Foo ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Foo ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Foo ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -10579,11 +10579,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -10731,10 +10731,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static Bar ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static Bar ParseFrom(pb::CodedInputStream input) {
+        public static Bar ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static Bar ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static Bar ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -10803,11 +10803,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -10965,10 +10965,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestDupFieldNumber ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestDupFieldNumber ParseFrom(pb::CodedInputStream input) {
+    public static TestDupFieldNumber ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestDupFieldNumber ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestDupFieldNumber ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -11043,11 +11043,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -11340,10 +11340,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static NestedMessage ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static NestedMessage ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static NestedMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -11417,11 +11417,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -11597,10 +11597,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestNestedMessageHasBits ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestNestedMessageHasBits ParseFrom(pb::CodedInputStream input) {
+    public static TestNestedMessageHasBits ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestNestedMessageHasBits ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestNestedMessageHasBits ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -11669,11 +11669,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -12059,10 +12059,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestCamelCaseFieldNames ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestCamelCaseFieldNames ParseFrom(pb::CodedInputStream input) {
+    public static TestCamelCaseFieldNames ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestCamelCaseFieldNames ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestCamelCaseFieldNames ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -12170,11 +12170,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -12710,10 +12710,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestFieldOrderings ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestFieldOrderings ParseFrom(pb::CodedInputStream input) {
+    public static TestFieldOrderings ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestFieldOrderings ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestFieldOrderings ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -12789,11 +12789,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -13276,10 +13276,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestExtremeDefaultValues ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestExtremeDefaultValues ParseFrom(pb::CodedInputStream input) {
+    public static TestExtremeDefaultValues ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestExtremeDefaultValues ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestExtremeDefaultValues ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -13402,11 +13402,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -13956,10 +13956,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static OneString ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static OneString ParseFrom(pb::CodedInputStream input) {
+    public static OneString ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static OneString ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static OneString ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -14028,11 +14028,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -14181,10 +14181,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static OneBytes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static OneBytes ParseFrom(pb::CodedInputStream input) {
+    public static OneBytes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static OneBytes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static OneBytes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -14253,11 +14253,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -14763,10 +14763,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestPackedTypes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestPackedTypes ParseFrom(pb::CodedInputStream input) {
+    public static TestPackedTypes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestPackedTypes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestPackedTypes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -14888,11 +14888,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -15769,10 +15769,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestUnpackedTypes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestUnpackedTypes ParseFrom(pb::CodedInputStream input) {
+    public static TestUnpackedTypes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestUnpackedTypes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestUnpackedTypes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -15894,11 +15894,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -16461,10 +16461,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestPackedExtensions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestPackedExtensions ParseFrom(pb::CodedInputStream input) {
+    public static TestPackedExtensions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestPackedExtensions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestPackedExtensions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -16531,11 +16531,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -16699,10 +16699,10 @@ namespace Google.ProtocolBuffers.TestProtos {
         public static DynamicMessageType ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
           return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
         }
-        public static DynamicMessageType ParseFrom(pb::CodedInputStream input) {
+        public static DynamicMessageType ParseFrom(pb::ICodedInputStream input) {
           return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
         }
-        public static DynamicMessageType ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        public static DynamicMessageType ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
           return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
         }
         public static Builder CreateBuilder() { return new Builder(); }
@@ -16771,11 +16771,11 @@ namespace Google.ProtocolBuffers.TestProtos {
             return this;
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input) {
+          public override Builder MergeFrom(pb::ICodedInputStream input) {
             return MergeFrom(input, pb::ExtensionRegistry.Empty);
           }
           
-          public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+          public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
             pb::UnknownFieldSet.Builder unknownFields = null;
             uint tag;
             string field_name;
@@ -17016,10 +17016,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestDynamicExtensions ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestDynamicExtensions ParseFrom(pb::CodedInputStream input) {
+    public static TestDynamicExtensions ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestDynamicExtensions ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestDynamicExtensions ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -17108,11 +17108,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -17596,10 +17596,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static TestRepeatedScalarDifferentTagSizes ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static TestRepeatedScalarDifferentTagSizes ParseFrom(pb::CodedInputStream input) {
+    public static TestRepeatedScalarDifferentTagSizes ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static TestRepeatedScalarDifferentTagSizes ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static TestRepeatedScalarDifferentTagSizes ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -17689,11 +17689,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -17998,10 +17998,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static FooRequest ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static FooRequest ParseFrom(pb::CodedInputStream input) {
+    public static FooRequest ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static FooRequest ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static FooRequest ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -18067,11 +18067,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -18181,10 +18181,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static FooResponse ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static FooResponse ParseFrom(pb::CodedInputStream input) {
+    public static FooResponse ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static FooResponse ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static FooResponse ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -18250,11 +18250,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -18364,10 +18364,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static BarRequest ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static BarRequest ParseFrom(pb::CodedInputStream input) {
+    public static BarRequest ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static BarRequest ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static BarRequest ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -18433,11 +18433,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -18547,10 +18547,10 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static BarResponse ParseDelimitedFrom(global::System.IO.Stream input, pb::ExtensionRegistry extensionRegistry) {
       return CreateBuilder().MergeDelimitedFrom(input, extensionRegistry).BuildParsed();
     }
-    public static BarResponse ParseFrom(pb::CodedInputStream input) {
+    public static BarResponse ParseFrom(pb::ICodedInputStream input) {
       return ((Builder) CreateBuilder().MergeFrom(input)).BuildParsed();
     }
-    public static BarResponse ParseFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+    public static BarResponse ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
     public static Builder CreateBuilder() { return new Builder(); }
@@ -18616,11 +18616,11 @@ namespace Google.ProtocolBuffers.TestProtos {
         return this;
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input) {
+      public override Builder MergeFrom(pb::ICodedInputStream input) {
         return MergeFrom(input, pb::ExtensionRegistry.Empty);
       }
       
-      public override Builder MergeFrom(pb::CodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+      public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;