Support const modifier in fields, variables

runtime/vm/ast.cc

 // Copyright (c) 2011, 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.
 
 #include "vm/ast.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/isolate.h"
 #include "vm/object_store.h"
 
@@ skipping 111 matching lines @@
   }
   const Instance* right_val = this->right()->EvalConstExpr();
   if (right_val == NULL) {
     return NULL;
   }
   switch (kind_) {
     case Token::kLT:
     case Token::kGT:
     case Token::kLTE:
     case Token::kGTE:
-      if (left_val->IsNumber() && right_val->IsNumber()) {
+      if ((left_val->IsNumber() || left_val->IsNull()) &&
+          (right_val->IsNumber() || right_val->IsNull())) {
         return &Bool::ZoneHandle(Bool::False());
       }
       return NULL;
     case Token::kEQ:
     case Token::kNE:
     case Token::kEQ_STRICT:
     case Token::kNE_STRICT:
       // The comparison is a compile time const if both operands are either a
       // number, string, or boolean value (but not necessarily the same type).
       if ((left_val->IsNumber() ||
           left_val->IsString() ||
-          left_val->IsBool()) &&
+          left_val->IsBool() ||
+          left_val->IsNull()) &&
           (right_val->IsNumber() ||
           right_val->IsString() ||
-          right_val->IsBool())) {
+          right_val->IsBool() ||
+          right_val->IsNull())) {
         return &Bool::ZoneHandle(Bool::False());
       }
       return NULL;
     default:
       return NULL;
   }
   return NULL;
 }
 
 
@@ skipping 210 matching lines @@
   if (result.IsError() || result.IsNull()) {
     // TODO(turnidge): We could get better error messages by returning
     // the Error object directly to the parser.  This will involve
     // replumbing all of the EvalConstExpr methods.
     return NULL;
   }
   return &Instance::ZoneHandle(Instance::Cast(result).raw());
 }
 
 }  // namespace dart