Fix wrong conversion from double to bigint in overriden operators of new bigint.

runtime/lib/bigint.dart

 // Copyright (c) 2014, 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.
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 /*
  * Copyright (c) 2003-2005  Tom Wu
@@ skipping 932 matching lines @@
   int pow(int exponent) {
     throw "Bigint.pow not implemented";
   }
 
   // Overriden operators and methods.
 
   // The following operators override operators of _IntegerImplementation for
   // efficiency, but are not necessary for correctness. They shortcut native
   // calls that would return null because the receiver is _Bigint.
   num operator +(num other) {
-    return other._toBigint()._addFromInteger(this);
+    return other._toBigintOrDouble()._addFromInteger(this);
   }
   num operator -(num other) {
-    return other._toBigint()._subFromInteger(this);
+    return other._toBigintOrDouble()._subFromInteger(this);
   }
   num operator *(num other) {
-    return other._toBigint()._mulFromInteger(this);
+    return other._toBigintOrDouble()._mulFromInteger(this);
   }
   num operator ~/(num other) {
     if ((other is int) && (other == 0)) {
       throw const IntegerDivisionByZeroException();
     }
-    return other._toBigint()._truncDivFromInteger(this);
+    return other._toBigintOrDouble()._truncDivFromInteger(this);
   }
-  num operator /(num other) {
-    return this.toDouble() / other.toDouble();
-  }
-  // TODO(regis): Investigate strange behavior with % double.INFINITY.
-  /*
   num operator %(num other) {
     if ((other is int) && (other == 0)) {
       throw const IntegerDivisionByZeroException();
     }
-    return other._toBigint()._moduloFromInteger(this);
+    return other._toBigintOrDouble()._moduloFromInteger(this);
   }
-  */
   int operator &(int other) {
-    return other._toBigint()._bitAndFromInteger(this);
+    return other._toBigintOrDouble()._bitAndFromInteger(this);
   }
   int operator |(int other) {
-    return other._toBigint()._bitOrFromInteger(this);
+    return other._toBigintOrDouble()._bitOrFromInteger(this);
   }
   int operator ^(int other) {
-    return other._toBigint()._bitXorFromInteger(this);
+    return other._toBigintOrDouble()._bitXorFromInteger(this);
   }
   int operator >>(int other) {
-    return other._toBigint()._shrFromInt(this);
+    return other._toBigintOrDouble()._shrFromInt(this);
   }
   int operator <<(int other) {
-    return other._toBigint()._shlFromInt(this);
+    return other._toBigintOrDouble()._shlFromInt(this);
   }
   // End of operator shortcuts.
 
   int operator -() {
     if (_used == 0) {
       return this;
     }
     var r = new _Bigint();
     _copyTo(r);
     r._neg = !_neg;
@@ skipping 194 matching lines @@
     _reduce(r);
   }
 
   // r = x*y/R mod _m ; x, y != r
   void _mulTo(_Bigint x, _Bigint y, _Bigint r) {
     x._mulTo(y, r);
     _reduce(r);
   }
 }