Remove unnecessary tuple creation.

src/Compilers/Core/Portable/Serialization/ObjectBinderState.cs

@@ -65,11 +65,8 @@ public int GetOrAddTypeId(Type type)
         public Type GetTypeFromId(int typeId)
             => _types[typeId];
 
-        public (Type, Func<ObjectReader, object>) GetTypeAndReaderFromId(int typeId)
-            => (_types[typeId], _typeReaders[typeId]);
-
-        public Func<ObjectReader, object> GetTypeReader(int index)
-            => _typeReaders[index];
+        public Func<ObjectReader, object> GetTypeReaderFromId(int typeId)
+            => _typeReaders[typeId];
 
         public bool RegisterTypeReader(Type type, Func<ObjectReader, object> typeReader)
         {

src/Compilers/Core/Portable/Serialization/StreamObjectReader.cs

@@ -577,17 +577,17 @@ public Type ReadType()
         private Type ReadTypeAfterTag()
             => _binderState.GetTypeFromId(this.ReadInt32());
 
-        private (Type, Func<ObjectReader, object>) ReadTypeAndReader()
+        private Func<ObjectReader, object> ReadTypeReader()
         {
             _reader.ReadByte();
-            return _binderState.GetTypeAndReaderFromId(this.ReadInt32());
+            return _binderState.GetTypeReaderFromId(this.ReadInt32());
         }
 
         private object ReadObject()
         {
-            int id = _objectReferenceMap.GetNextReferenceId();
+            var id = _objectReferenceMap.GetNextReferenceId();
 
-            var (type, typeReader) = this.ReadTypeAndReader();
+            var typeReader = this.ReadTypeReader();
 
             // recursive: read and construct instance immediately from member elements encoding next in the stream
             var instance = typeReader(this);