Special case -0.0 when constant folding.

dart/frog/leg/lib/js_helper.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.
 
 #library('js_helper');
 
 #import('coreimpl.dart');
 
 #source('date_helper.dart');
 #source('regexp_helper.dart');
@@ skipping 1123 matching lines @@
     }
     var ret = JS('num', @'parseInt($0, 10)', str);
     if (ret.isNaN()) throw new BadNumberFormatException(str);
     return ret;
   }
 
   static double parseDouble(String str) {
     checkNull(str);
     if (str is !String) throw new IllegalArgumentException();
     var ret = JS('num', @'parseFloat($0)', str);
-    if (ret.isNaN() && str != 'NaN') throw new BadNumberFormatException(str);
+    if (ret == 0 && (str.startsWith("0x") || str.startsWith("0X"))) {
+      // TODO(ahe): This is unspecified, but tested by co19.

[floitsch, 2012/02/29 15:33:46]

please file a bug that this should not be allowed.

[ahe, 2012/02/29 18:42:55]

I have filed a co19 bug.

+      ret = JS('num', @'parseInt($0)', str);
+    }
+    if (ret.isNaN() && str != 'NaN' && str != '-NaN') {
+      throw new BadNumberFormatException(str);
+    }
     return ret;
   }
 
   static double sqrt(num value)
     => JS('double', @'Math.sqrt($0)', checkNum(value));
 
   static double sin(num value)
     => JS('double', @'Math.sin($0)', checkNum(value));
 
   static double cos(num value)
@@ skipping 126 matching lines @@
       }
     }
   } else if (JS('bool', @'$0 instanceof RangeError', ex)) {
     var message = JS('String', @'$0.message', ex);
     if (message.contains('call stack')) {
       return new StackOverflowException();
     }
   }
   return ex;
 }