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

test/codegen/expect/sunflower/sunflower.js

Index: test/codegen/expect/sunflower/sunflower.js
diff --git a/test/codegen/expect/sunflower/sunflower.js b/test/codegen/expect/sunflower/sunflower.js
index ec7f75ccde32fc1c5167476ed1fef91e27ae5798..632890c16d35fc872ace761cbe2dd47867791c77 100644
--- a/test/codegen/expect/sunflower/sunflower.js
+++ b/test/codegen/expect/sunflower/sunflower.js
@@ -45,16 +45,35 @@ var sunflower;
     }
     exports.notes.textContent = `${exports.seeds} seeds`;
   }
+  let x$ = Symbol('x');
+  let y$ = Symbol('y');
+  let radius$ = Symbol('radius');
+  let color = Symbol('color');
   class Circle extends core.Object {
+    get x() {
+      return this[x$];
+    }
+    get y() {
+      return this[y$];
+    }
+    get radius() {
+      return this[radius$];
+    }
     Circle(x, y, radius) {
-      this.x = x;
-      this.y = y;
-      this.radius = radius;
+      this[x$] = x;
+      this[y$] = y;
+      this[radius$] = radius;
     }
   }
   class CirclePainter extends core.Object {
     CirclePainter() {
-      this.color = ORANGE;
+      this[color] = ORANGE;
+    }
+    get color() {
+      return this[color];
+    }
+    set color(value) {
+      this[color] = value;
     }
     draw() {
       exports.context.beginPath();