Change new List(n) to return fixed length list.

pkg/fixnum/lib/src/int32.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.
 
 part of fixnum;
 
 /**
  * An immutable 32-bit signed integer, in the range [-2^31, 2^31 - 1].
  * Arithmetic operations may overflow in order to maintain this range.
  */
@@ skipping 270 matching lines @@
   bool operator ==(other) {
     if (other == null) {
       return false;
     }
     if (other is int64) {
       return this.toInt64() == other;
     }
     return _i == _convert(other);
   }
 
-  int compareTo(other) {
+  int compareTo(Comparable other) {
     if (other is int64) {
       return this.toInt64().compareTo(other);
     }
     return _i.compareTo(_convert(other));
   }
 
   bool operator <(other) {
     if (other is int64) {
       return this.toInt64() < other;
     }
@@ skipping 29 matching lines @@
   bool get isZero => _i == 0;
 
   int get hashCode => _i;
 
   int32 abs() => _i < 0 ? new int32.fromInt(-_i) : this;
 
   int numberOfLeadingZeros() => _numberOfLeadingZeros(_i);
   int numberOfTrailingZeros() => _numberOfTrailingZeros(_i);
 
   List<int> toBytes() {
-    List<int> result = new List<int>.fixedLength(4);
+    List<int> result = new List<int>(4);
     result[0] = _i & 0xff;
     result[1] = (_i >> 8) & 0xff;
     result[2] = (_i >> 16) & 0xff;
     result[3] = (_i >> 24) & 0xff;
     return result;
   }
 
   int toInt() => _i;
   int32 toInt32() => this;
   int64 toInt64() => new int64.fromInt(_i);
 
   String toString() => _i.toString();
   String toHexString() => _i.toRadixString(16);
   String toRadixString(int radix) => _i.toRadixString(radix);
 }