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

lib/runtime/dart/_internal.js

Index: lib/runtime/dart/_internal.js
diff --git a/lib/runtime/dart/_internal.js b/lib/runtime/dart/_internal.js
index e36185334575891a2ca963503fd104d47d6bbf64..af6ab2781ba8e1ecd680fd3403f4336b86531b1d 100644
--- a/lib/runtime/dart/_internal.js
+++ b/lib/runtime/dart/_internal.js
@@ -320,10 +320,10 @@ var _internal;
   let ListIterator$ = dart.generic(function(E) {
     class ListIterator extends core.Object {
       ListIterator(iterable) {
-        this[_iterable] = iterable;
-        this[_length] = iterable[core.$length];
-        this[_index] = 0;
-        this[_current] = null;
+        dart.initField(ListIterator, this, _iterable, iterable);
+        dart.initField(ListIterator, this, _length, iterable[core.$length]);
+        dart.initField(ListIterator, this, _index, 0);
+        dart.initField(ListIterator, this, _current, null);
       }
       get current() {
         return this[_current];
@@ -510,10 +510,10 @@ var _internal;
   let ExpandIterator$ = dart.generic(function(S, T) {
     class ExpandIterator extends core.Object {
       ExpandIterator(iterator, f) {
-        this[_iterator] = iterator;
-        this[_f] = f;
-        this[_currentExpansion] = dart.as(new EmptyIterator(), core.Iterator$(T));
-        this[_current] = null;
+        dart.initField(ExpandIterator, this, _iterator, iterator);
+        dart.initField(ExpandIterator, this, _f, f);
+        dart.initField(ExpandIterator, this, _currentExpansion, dart.as(new EmptyIterator(), core.Iterator$(T)));
+        dart.initField(ExpandIterator, this, _current, null);
       }
       [_nextExpansion]() {}
       get current() {
@@ -1396,7 +1396,7 @@ var _internal;
   let ListMapView$ = dart.generic(function(E) {
     class ListMapView extends core.Object {
       ListMapView(values) {
-        this[_values] = values;
+        dart.initField(ListMapView, this, _values, values);
       }
       get(key) {
         return this.containsKey(key) ? this[_values][core.$get](key) : null;
@@ -1837,13 +1837,13 @@ var _internal;
   let _name = dart.JsSymbol('_name');
   class Symbol extends core.Object {
     Symbol(name) {
-      this[_name] = name;
+      dart.initField(Symbol, this, _name, name);
     }
     unvalidated(name) {
-      this[_name] = name;
+      dart.initField(Symbol, this, _name, name);
     }
     validated(name) {
-      this[_name] = Symbol.validatePublicSymbol(name);
+      dart.initField(Symbol, this, _name, Symbol.validatePublicSymbol(name));
     }
     ['=='](other) {
       return dart.is(other, Symbol) && dart.equals(this[_name], dart.dload(other, _name));