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

test/codegen/expect/constructors.js

Index: test/codegen/expect/constructors.js
diff --git a/test/codegen/expect/constructors.js b/test/codegen/expect/constructors.js
index 4fb06b7c78bdcf4b32eb76d6eb90753fddf2edc8..5bfee7fbf9c0c3e23ce4715dede231bd15e584f3 100644
--- a/test/codegen/expect/constructors.js
+++ b/test/codegen/expect/constructors.js
@@ -26,7 +26,7 @@ var constructors;
   dart.defineNamedConstructor(D, 'named');
   class E extends core.Object {
     E(name) {
-      this.name = name;
+      dart.initField(E, this, 'name', name);
     }
   }
   class F extends E {
@@ -47,31 +47,31 @@ var constructors;
   }
   class I extends core.Object {
     I() {
-      this.name = 'default';
+      dart.initField(I, this, 'name', 'default');
     }
     named(name) {
-      this.name = name;
+      dart.initField(I, this, 'name', name);
     }
   }
   dart.defineNamedConstructor(I, 'named');
   class J extends core.Object {
     J() {
-      this.initialized = true;
-      this.nonInitialized = null;
+      dart.initField(J, this, 'initialized', true);
+      dart.initField(J, this, 'nonInitialized', null);
     }
   }
   class K extends core.Object {
     K() {
-      this.s = 'a';
+      dart.initField(K, this, 's', 'a');
     }
     withS(s) {
-      this.s = s;
+      dart.initField(K, this, 's', s);
     }
   }
   dart.defineNamedConstructor(K, 'withS');
   class L extends core.Object {
     L(foo) {
-      this.foo = foo;
+      dart.initField(L, this, 'foo', foo);
     }
   }
   class M extends L {