fixes #52, fields shadowing getters/setters or other fields

lib/runtime/dart/convert.js

 var convert;
 (function(exports) {
   'use strict';
   let ASCII = new AsciiCodec();
   let _ASCII_MASK = 127;
   let _allowInvalid = Symbol('_allowInvalid');
   let _nameToEncoding = Symbol('_nameToEncoding');
   let Codec$ = dart.generic(function(S, T) {
     class Codec extends core.Object {
       Codec() {
@@ skipping 316 matching lines @@
       this[_sink] = sink;
       super.ByteConversionSinkBase();
     }
     add(chunk) {
       return this[_sink].add(chunk);
     }
     close() {
       return this[_sink].close();
     }
   }
+  let _INITIAL_BUFFER_SIZE = Symbol('_INITIAL_BUFFER_SIZE');
   let _buffer = Symbol('_buffer');
-  let _INITIAL_BUFFER_SIZE = Symbol('_INITIAL_BUFFER_SIZE');
   let _callback = Symbol('_callback');
   let _bufferIndex = Symbol('_bufferIndex');
   let _roundToPowerOf2 = Symbol('_roundToPowerOf2');
   class _ByteCallbackSink extends ByteConversionSinkBase {
     _ByteCallbackSink(callback) {
       this[_buffer] = new typed_data.Uint8List(_ByteCallbackSink[_INITIAL_BUFFER_SIZE]);
       this[_callback] = callback;
       this[_bufferIndex] = 0;
       super.ByteConversionSinkBase();
     }
@@ skipping 142 matching lines @@
       }
     }
     return _FusedConverter;
   });
   let _FusedConverter = _FusedConverter$();
   let HTML_ESCAPE = new HtmlEscape();
   let _ = Symbol('_');
   let _name = Symbol('_name');
   class HtmlEscapeMode extends core.Object {
     [_](name, escapeLtGt, escapeQuot, escapeApos, escapeSlash) {
-      this[_name] = name;
-      this.escapeLtGt = escapeLtGt;
-      this.escapeQuot = escapeQuot;
-      this.escapeApos = escapeApos;
-      this.escapeSlash = escapeSlash;
+      dart.initField(HtmlEscapeMode, this, _name, name);
+      dart.initField(HtmlEscapeMode, this, 'escapeLtGt', escapeLtGt);
+      dart.initField(HtmlEscapeMode, this, 'escapeQuot', escapeQuot);
+      dart.initField(HtmlEscapeMode, this, 'escapeApos', escapeApos);
+      dart.initField(HtmlEscapeMode, this, 'escapeSlash', escapeSlash);
     }
     toString() {
       return this[_name];
     }
   }
   dart.defineNamedConstructor(HtmlEscapeMode, _);
   HtmlEscapeMode.UNKNOWN = new HtmlEscapeMode[_]('unknown', true, true, true, true);
   HtmlEscapeMode.ATTRIBUTE = new HtmlEscapeMode[_]('attribute', false, true, false, false);
   HtmlEscapeMode.ELEMENT = new HtmlEscapeMode[_]('element', true, false, false, true);
   let _convert = Symbol('_convert');
   class HtmlEscape extends Converter$(core.String, core.String) {
     HtmlEscape(mode) {
       if (mode === void 0)
         mode = HtmlEscapeMode.UNKNOWN;
-      this.mode = mode;
+      dart.initField(HtmlEscape, this, 'mode', mode);
       super.Converter();
     }
     convert(text) {
       let val = this[_convert](text, 0, text.length);
       return val == null ? text : val;
     }
     [_convert](text, start, end) {
       let result = null;
       for (let i = start; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + 1) {
         let ch = core.String.get(text, i);
@@ skipping 74 matching lines @@
           this[_sink].close();
       }
     }
     close() {
       return this[_sink].close();
     }
   }
   class JsonUnsupportedObjectError extends core.Error {
     JsonUnsupportedObjectError(unsupportedObject, opts) {
       let cause = opts && 'cause' in opts ? opts.cause : null;
-      this.unsupportedObject = unsupportedObject;
-      this.cause = cause;
+      dart.initField(JsonUnsupportedObjectError, this, 'unsupportedObject', unsupportedObject);
+      dart.initField(JsonUnsupportedObjectError, this, 'cause', cause);
       super.Error();
     }
     toString() {
       if (this.cause != null) {
         return "Converting object to an encodable object failed.";
       } else {
         return "Converting object did not return an encodable object.";
       }
     }
   }
@@ skipping 47 matching lines @@
         return new JsonDecoder();
       return new JsonDecoder(this[_reviver]);
     }
   }
   dart.defineNamedConstructor(JsonCodec, 'withReviver');
   let _utf8Encode = Symbol('_utf8Encode');
   class JsonEncoder extends Converter$(core.Object, core.String) {
     JsonEncoder(toEncodable) {
       if (toEncodable === void 0)
         toEncodable = null;
-      this.indent = null;
+      dart.initField(JsonEncoder, this, 'indent', null);
       this[_toEncodable$] = toEncodable;
       super.Converter();
     }
     withIndent(indent, toEncodable) {
       if (toEncodable === void 0)
         toEncodable = null;
-      this.indent = indent;
+      dart.initField(JsonEncoder, this, 'indent', indent);
       this[_toEncodable$] = toEncodable;
       super.Converter();
     }
     convert(object) {
       return _JsonStringStringifier.stringify(object, dart.as(this[_toEncodable$], dart.functionType(dart.dynamic, [dart.dynamic])), this.indent);
     }
     startChunkedConversion(sink) {
       if (!dart.is(sink, StringConversionSink)) {
         sink = new StringConversionSink.from(sink);
       } else if (dart.is(sink, _Utf8EncoderSink)) {
@@ skipping 1732 matching lines @@
   exports.LineSplitter = LineSplitter;
   exports.StringConversionSink = StringConversionSink;
   exports.ClosableStringSink = ClosableStringSink;
   exports.UNICODE_REPLACEMENT_CHARACTER_RUNE = UNICODE_REPLACEMENT_CHARACTER_RUNE;
   exports.UNICODE_BOM_CHARACTER_RUNE = UNICODE_BOM_CHARACTER_RUNE;
   exports.UTF8 = UTF8;
   exports.Utf8Codec = Utf8Codec;
   exports.Utf8Encoder = Utf8Encoder;
   exports.Utf8Decoder = Utf8Decoder;
 })(convert || (convert = {}));