Enable is and as checks on non-ground types

lib/src/info.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.
 
 /// Defines static information collected by the type checker and used later by
 /// emitters to generate code.
 library dev_compiler.src.info;
 
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
@@ skipping 446 matching lines @@
   final DartType expectedType;
 
   InvalidParameterDeclaration(
       TypeRules rules, FormalParameter declaration, this.expectedType)
       : super(declaration);
 
   @override List<Object> get arguments => [node, expectedType];
   @override String get message => 'Type check failed: {0} is not of type {1}';
 }
 
-class InvalidRuntimeCheckError extends StaticError {
+class NonGroundTypeCheckInfo extends StaticInfo {
   final DartType type;
+  final AstNode node;
 
-  InvalidRuntimeCheckError(AstNode node, this.type) : super(node) {
+  NonGroundTypeCheckInfo(this.node, this.type) {
     assert(node is IsExpression || node is AsExpression);
   }
 
   @override List<Object> get arguments => [type];
-  String get message => "Invalid runtime check on non-ground type {0}";
+  String get message =>
+      "Runtime check on non-ground type {0} may throw StrongModeError";
+
+  toErrorCode() => new HintCode(name, message);
 }
 
 // Invalid override of an instance member of a class.
 abstract class InvalidOverride extends StaticError {
   /// Member declaration with the invalid override.
   final ExecutableElement element;
 
   /// Type (class or interface) that provides the base declaration.
   final InterfaceType base;
 
@@ skipping 83 matching lines @@
 /// Better to have `super` at the end, as required by the Dart style guide:
 /// <http://goo.gl/q1T4BB>
 ///
 /// For now this is the only pattern we support.
 class InvalidSuperInvocation extends StaticError {
   InvalidSuperInvocation(SuperConstructorInvocation node) : super(node);
 
   @override String get message => "super call must be last in an initializer "
       "list (see http://goo.gl/q1T4BB): {0}";
 }