Fixed some static type warnings in vm core libraries

runtime/lib/integers.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.
 
 // TODO(srdjan): fix limitations.
 // - shift amount must be a Smi.
 class IntegerImplementation {
   factory IntegerImplementation._uninstantiable() {
     throw const UnsupportedOperationException(
         "IntegerImplementation can only be allocated by the VM");
@@ skipping 123 matching lines @@
   }
   String toStringAsPrecision(int precision) {
     return this.toDouble().toStringAsPrecision(precision);
   }
   String toRadixString(int radix) {
     final table = const ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
                          "A", "B", "C", "D", "E", "F"];
     if ((radix <= 1) || (radix > 16)) {
       throw "Bad radix: $radix";
     }
-    final bool isNegative = this < 0;
-    var value = isNegative ? -this : this;
+    var value = this.isNegative() ? -this : this;

[Ivan Posva, 2012/03/14 05:34:05]

Please maintain the code as it was with a local variable. If you really want to
avoid the hiding of the name then please use a different variable name:
final negative = this.isNegative();
var value = negative ? -this : this;
...
if (negative) {
  buffer.add("-");
}

Actually on second thought, I do like the name isNegative and there is a reason
why we allow shadowing.

[zundel, 2012/03/14 13:04:34]

np, I'll revert this. 

Background: the shadowing warning is not in the spec,we were thinking it could
be optionally flipped on/off for developers that wanted it (currently there is
no way to turn it off).

     List temp = new List();
     while (value > 0) {
       var digit = value % radix;
       value ~/= radix;
       temp.add(digit);
     }
     if (temp.isEmpty()) {
       return "0";
     }
     StringBuffer buffer = new StringBuffer();
-    if (isNegative) buffer.add("-");
+    if (this.isNegative()) buffer.add("-");
     for (int i = temp.length - 1; i >= 0; i--) {
       buffer.add(table[temp[i]]);
     }
     return buffer.toString();
   }
 }
 
 class Smi extends IntegerImplementation implements int {
   factory Smi._uninstantiable() {
     throw const UnsupportedOperationException(
@@ skipping 52 matching lines @@
     }
   }
   int shlFromInt(int other) {
     throw const OutOfMemoryException();
   }
 
   int pow(int exponent) {
     throw "Bigint.pow not implemented";
   }
 }