All strong mode cleaning of dart2js.

pkg/compiler/lib/src/js_backend/constant_emitter.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.
 
 import '../common.dart';
 import '../common_elements.dart';
 import '../constants/values.dart';
 import '../elements/elements.dart';
+import '../elements/types.dart' show TypeVariableType;
 import '../elements/entities.dart';
 import '../elements/resolution_types.dart';
 import '../io/code_output.dart';
 import '../js/js.dart' as jsAst;
 import '../js/js.dart' show js;
 import '../js_emitter/code_emitter_task.dart';
 import '../options.dart';
 import '../universe/world_builder.dart';
 import 'constant_system_javascript.dart';
 import 'js_backend.dart';
@@ skipping 318 matching lines @@
         !type.treatAsRaw &&
         _rtiNeed.classNeedsRti(type.element)) {
       return new jsAst.Call(
           getHelperProperty(_commonElements.setRuntimeTypeInfo),
           [value, _reifiedTypeArguments(type)]);
     }
     return value;
   }
 
   jsAst.Expression _reifiedTypeArguments(ResolutionInterfaceType type) {
-    jsAst.Expression unexpected(ResolutionTypeVariableType variable) {
+    jsAst.Expression unexpected(TypeVariableType _variable) {
+      ResolutionTypeVariableType variable = _variable;
       throw new SpannableAssertionFailure(
           NO_LOCATION_SPANNABLE,
           "Unexpected type variable '${variable.getStringAsDeclared(null)}'"
           " in constant type '${type.getStringAsDeclared(null)}'");
     }
 
     List<jsAst.Expression> arguments = <jsAst.Expression>[];
     for (ResolutionDartType argument in type.typeArguments) {
       arguments.add(
           _rtiEncoder.getTypeRepresentation(_emitter, argument, unexpected));
     }
     return new jsAst.ArrayInitializer(arguments);
   }
 
   @override
   jsAst.Expression visitDeferred(DeferredConstantValue constant, [_]) {
     return constantReferenceGenerator(constant.referenced);
   }
 }