Throw FormatException when Int32/Int64.parseRadix() encounters bad digit

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 53 matching lines @@
   // TODO(rice) - Make this faster by converting several digits at once.
   static Int32 parseRadix(String s, int radix) {
     if ((radix <= 1) || (radix > 16)) {
       throw new ArgumentError("Bad radix: $radix");
     }
     Int32 x = ZERO;
     for (int i = 0; i < s.length; i++) {
       int c = s.codeUnitAt(i);
       int digit = _decodeDigit(c);
       if (digit < 0 || digit >= radix) {
-        throw new Exception("Non-radix code unit: $c");
+        throw new FormatException("Non-radix code unit: $c");
       }
       x = (x * radix) + digit;
     }
     return x;
   }
 
   /**
    * Parses a decimal [String] and returns an [Int32].
    */
   static Int32 parseInt(String s) => new Int32(int.parse(s));
@@ skipping 290 matching lines @@
 
   double toDouble() => _i.toDouble();
   int toInt() => _i;
   Int32 toInt32() => this;
   Int64 toInt64() => new Int64(_i);
 
   String toString() => _i.toString();
   String toHexString() => _i.toRadixString(16);
   String toRadixString(int radix) => _i.toRadixString(radix);
 }