Typing fixes to eliminate casts/dcalls

test/checker/checker_test.dart

 // Copyright (c) 2015, 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.
 
 /// General type checking tests
 library dev_compiler.test.checker_test;
 
 import 'package:unittest/unittest.dart';
 
 import 'package:dev_compiler/src/testing.dart';
@@ skipping 19 matching lines @@
           _Predicate _validKey;
 
           // Initializing _comparator needs a cast, since K may not always be
           // Comparable.
           // Initializing _validKey shouldn't need a cast.  Currently
           // it requires inference to work because of dartbug.com/23381
           SplayTreeMap([int compare(K key1, K key2),
                         bool isValidKey(potentialKey)]) {
             : _comparator = /*warning:DownCastComposite*/(compare == null) ? Comparable.compare : compare,
               _validKey = /*info:InferredType should be pass*/(isValidKey != null) ? isValidKey : ((v) => true);
+              _Predicate<Object> _v = /*warning:DownCastComposite*/(isValidKey != null) ? isValidKey : ((v) => true);
+              _v = /*info:InferredType should be pass*/(isValidKey != null) ? _v : ((v) => true);
           }
         }
         void main() {
         }
       '''
     });
   });
 
   test('dynamic invocation', () {
     testChecker({
@@ skipping 2863 matching lines @@
             f = bar as II2D;
             f = bar as DD2I;
             f = bar as DI2D;
             f = bar as ID2D;
             f = bar as DD2D;
           }
       '''
     });
   });
 }