Typecheck constructor initializers properly

test/dart_codegen/expect/convert/byte_conversion.dart

 part of dart.convert;
  abstract class ByteConversionSink extends ChunkedConversionSink<List<int>> {ByteConversionSink();
  factory ByteConversionSink.withCallback(void callback(List<int> accumulated)) = _ByteCallbackSink;
  factory ByteConversionSink.from(Sink<List<int>> sink) = _ByteAdapterSink;
  void addSlice(List<int> chunk, int start, int end, bool isLast);
 }
  abstract class ByteConversionSinkBase extends ByteConversionSink {void add(List<int> chunk);
  void close();
  void addSlice(List<int> chunk, int start, int end, bool isLast) {
 add(chunk.sublist(start, end));
  if (isLast) close();
 }
 }
  class _ByteAdapterSink extends ByteConversionSinkBase {final Sink<List<int>> _sink;
  _ByteAdapterSink(this._sink);
  void add(List<int> chunk) => _sink.add(chunk);
  void close() => _sink.close();
 }
  class _ByteCallbackSink extends ByteConversionSinkBase {static const _INITIAL_BUFFER_SIZE = 1024;
  final _ChunkedConversionCallback<List<int>> _callback;
- List<int> _buffer = new Uint8List(_INITIAL_BUFFER_SIZE);
+ List<int> _buffer = new Uint8List(DDC$RT.cast(_INITIAL_BUFFER_SIZE, dynamic, int, "CastGeneral", """line 81, column 37 of dart:convert/byte_conversion.dart: """, _INITIAL_BUFFER_SIZE is int, true));
  int _bufferIndex = 0;
  _ByteCallbackSink(void callback(List<int> accumulated)) : this._callback = callback;
  void add(Iterable<int> chunk) {
 int freeCount = _buffer.length - _bufferIndex;
  if (chunk.length > freeCount) {
 int oldLength = _buffer.length;
  int newLength = _roundToPowerOf2(chunk.length + oldLength) * 2;
  List<int> grown = new Uint8List(newLength);
  grown.setRange(0, _buffer.length, _buffer);
  _buffer = grown;
 }
  _buffer.setRange(_bufferIndex, _bufferIndex + chunk.length, chunk);
  _bufferIndex += chunk.length;
 }
  static int _roundToPowerOf2(int v) {
 assert (v > 0); v--;
  v |= v >> 1;
  v |= v >> 2;
  v |= v >> 4;
  v |= v >> 8;
  v |= v >> 16;
  v++;
  return v;
 }
  void close() {
 _callback(_buffer.sublist(0, _bufferIndex));
 }
 }