Insert implicit downcasts in kernel strong mode.

pkg/kernel/lib/verifier.dart

 // Copyright (c) 2016, 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.
 library kernel.checks;
 
 import 'ast.dart';
 import 'transformations/flags.dart';
 
 void verifyProgram(Program program) {
   VerifyingVisitor.check(program);
@@ skipping 220 matching lines @@
     visitWithLocalScope(node);
   }
 
   visitVariableDeclaration(VariableDeclaration node) {
     visitChildren(node);
     declareVariable(node);
   }
 
   visitVariableGet(VariableGet node) {
     checkVariableInScope(node.variable, node);
+    visitChildren(node);
   }
 
   visitVariableSet(VariableSet node) {
     checkVariableInScope(node.variable, node);
     visitChildren(node);
   }
 
   @override
   visitStaticGet(StaticGet node) {
     visitChildren(node);
@@ skipping 190 matching lines @@
       throw 'Parent pointer on ${node.runtimeType} '
           'is ${node.parent.runtimeType} '
           'but should be ${parent.runtimeType}';
     }
     var oldParent = parent;
     parent = node;
     node.visitChildren(this);
     parent = oldParent;
   }
 }