Frog: preserve initialization order.

frog/value.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 
 interface CallingContext {
   MemberSet findMembers(String name);
   CounterLog get counters();
   Library get library();
   bool get isStatic();
@@ skipping 1326 matching lines @@
           isConst && other.isConst, node.span);
     }
 
     return super.binop(kind, other, context, node);
   }
 }
 
 
 class ObjectValue extends EvaluatedValue {
   final Map<FieldMember, Value> fields;
+  final List<FieldMember> fieldsInInitOrder;
   bool seenNativeInitializer = false;
 
   String _code;
 
   ObjectValue(bool isConst, Type type, SourceSpan span):
-    fields = {}, super(isConst, type, span);
+    fields = {}, fieldsInInitOrder = [], super(isConst, type, span);
 
   String get code() {
     if (_code === null) validateInitialized(null);
     return _code;
   }
 
   initFields() {
     var allMembers = world.gen._orderValues(type.genericType.getAllMembers());
     for (var f in allMembers) {
       if (f.isField && !f.isStatic && f.declaringType.isClass) {
-        fields[f] = f.computeValue();
+        _replaceField(f, f.computeValue(), true);
       }
     }
   }
 
   setField(Member field, Value value, [bool duringInit = false]) {
     // Unpack constant values
     if (value.isConst && value is VariableValue) {
       value = value.dynamic.value;
     }
     var currentValue = fields[field];
     if (isConst && !value.isConst) {
       world.error('used of non-const value in const intializer', value.span);
     }
 
     if (currentValue === null) {
-      fields[field] = value;
+      _replaceField(field, value, duringInit);
       if (field.isFinal && !duringInit) {
         world.error('cannot initialize final fields outside of initializer',
           value.span);
       }
     } else {
       // TODO(jimhug): Clarify spec on reinitializing fields with defaults.
       if (field.isFinal && field.computeValue() === null) {
         world.error('reassignment of field not allowed', value.span,
           field.span);
       } else {
-        fields[field] = value; //currentValue.union(value);
+        _replaceField(field, value, duringInit);
       }
     }
   }
 
+  _replaceField(Member field, Value value, bool duringInit) {
+    if (duringInit) {
+      for (int i = 0; i < fieldsInInitOrder.length; i++) {
+        if (fieldsInInitOrder[i] == field) {
+          fieldsInInitOrder[i] = null;
+          break;
+        }
+      }
+      // TODO(sra): What if the overridden value contains an effect?
+      fieldsInInitOrder.add(field);
+    }
+    fields[field] = value; //currentValue.union(value);
+  }
+
   validateInitialized(SourceSpan span) {
     var buf = new StringBuffer();
     buf.add('Object.create(');
     buf.add('${type.jsname}.prototype, ');
 
     buf.add('{');
     bool addComma = false;
     for (var field in fields.getKeys()) {
       if (addComma) buf.add(', ');
       buf.add(field.name);
@@ skipping 232 matching lines @@
     }
     return super.unop(kind, context, node);
   }
   Value binop(int kind, var other, CallingContext context, var node) {
     if (value != null) {
       return replaceValue(value.binop(kind, _unwrap(other), context, node));
     }
     return super.binop(kind, other, context, node);
   }
 }