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

lib/runtime/dart/convert.js

Index: lib/runtime/dart/convert.js
diff --git a/lib/runtime/dart/convert.js b/lib/runtime/dart/convert.js
index 2447a47b7a79b8c30e3184b1293ba96d382e4493..13c67dc908553e38f781204b0bb372efc362b138 100644
--- a/lib/runtime/dart/convert.js
+++ b/lib/runtime/dart/convert.js
@@ -334,8 +334,8 @@ var convert;
       return this[_sink].close();
     }
   }
-  let _buffer = Symbol('_buffer');
   let _INITIAL_BUFFER_SIZE = Symbol('_INITIAL_BUFFER_SIZE');
+  let _buffer = Symbol('_buffer');
   let _callback = Symbol('_callback');
   let _bufferIndex = Symbol('_bufferIndex');
   let _roundToPowerOf2 = Symbol('_roundToPowerOf2');
@@ -494,15 +494,31 @@ var convert;
   });
   let _FusedConverter = _FusedConverter$();
   let HTML_ESCAPE = new HtmlEscape();
+  let escapeLtGt$ = Symbol('escapeLtGt');
+  let escapeQuot$ = Symbol('escapeQuot');
+  let escapeApos$ = Symbol('escapeApos');
+  let escapeSlash$ = Symbol('escapeSlash');
   let _ = Symbol('_');
   let _name = Symbol('_name');
   class HtmlEscapeMode extends core.Object {
+    get escapeLtGt() {
+      return this[escapeLtGt$];
+    }
+    get escapeQuot() {
+      return this[escapeQuot$];
+    }
+    get escapeApos() {
+      return this[escapeApos$];
+    }
+    get escapeSlash() {
+      return this[escapeSlash$];
+    }
     [_](name, escapeLtGt, escapeQuot, escapeApos, escapeSlash) {
       this[_name] = name;
-      this.escapeLtGt = escapeLtGt;
-      this.escapeQuot = escapeQuot;
-      this.escapeApos = escapeApos;
-      this.escapeSlash = escapeSlash;
+      this[escapeLtGt$] = escapeLtGt;
+      this[escapeQuot$] = escapeQuot;
+      this[escapeApos$] = escapeApos;
+      this[escapeSlash$] = escapeSlash;
     }
     toString() {
       return this[_name];
@@ -512,12 +528,16 @@ var convert;
   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 mode$ = Symbol('mode');
   let _convert = Symbol('_convert');
   class HtmlEscape extends Converter$(core.String, core.String) {
+    get mode() {
+      return this[mode$];
+    }
     HtmlEscape(mode) {
       if (mode === void 0)
         mode = HtmlEscapeMode.UNKNOWN;
-      this.mode = mode;
+      this[mode$] = mode;
       super.Converter();
     }
     convert(text) {
@@ -609,11 +629,19 @@ var convert;
       return this[_sink].close();
     }
   }
+  let unsupportedObject$ = Symbol('unsupportedObject');
+  let cause$ = Symbol('cause');
   class JsonUnsupportedObjectError extends core.Error {
+    get unsupportedObject() {
+      return this[unsupportedObject$];
+    }
+    get cause() {
+      return this[cause$];
+    }
     JsonUnsupportedObjectError(unsupportedObject, opts) {
       let cause = opts && 'cause' in opts ? opts.cause : null;
-      this.unsupportedObject = unsupportedObject;
-      this.cause = cause;
+      this[unsupportedObject$] = unsupportedObject;
+      this[cause$] = cause;
       super.Error();
     }
     toString() {
@@ -676,19 +704,23 @@ var convert;
     }
   }
   dart.defineNamedConstructor(JsonCodec, 'withReviver');
+  let indent$ = Symbol('indent');
   let _utf8Encode = Symbol('_utf8Encode');
   class JsonEncoder extends Converter$(core.Object, core.String) {
+    get indent() {
+      return this[indent$];
+    }
     JsonEncoder(toEncodable) {
       if (toEncodable === void 0)
         toEncodable = null;
-      this.indent = null;
+      this[indent$] = null;
       this[_toEncodable$] = toEncodable;
       super.Converter();
     }
     withIndent(indent, toEncodable) {
       if (toEncodable === void 0)
         toEncodable = null;
-      this.indent = indent;
+      this[indent$] = indent;
       this[_toEncodable$] = toEncodable;
       super.Converter();
     }