| Index: src/objects-printer.cc | 
| diff --git a/src/objects-printer.cc b/src/objects-printer.cc | 
| index e86059b7198631ce25d32437c35cd9cc9b64155c..5d9c517f4d243d528b8e7e11b012ef4983cabfcc 100644 | 
| --- a/src/objects-printer.cc | 
| +++ b/src/objects-printer.cc | 
| @@ -64,6 +64,11 @@ void HeapObject::HeapObjectPrint(FILE* out) { | 
| case HEAP_NUMBER_TYPE: | 
| HeapNumber::cast(this)->HeapNumberPrint(out); | 
| break; | 
| +    case MUTABLE_HEAP_NUMBER_TYPE: | 
| +      PrintF(out, "<mutable "); | 
| +      HeapNumber::cast(this)->HeapNumberPrint(out); | 
| +      PrintF(out, ">"); | 
| +      break; | 
| case FIXED_DOUBLE_ARRAY_TYPE: | 
| FixedDoubleArray::cast(this)->FixedDoubleArrayPrint(out); | 
| break; | 
|  |