All strong mode cleaning of dart2js.

pkg/compiler/lib/src/constants/evaluation.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.
 
 library dart2js.constants.evaluation;
 
 import '../common.dart';
 import '../common_elements.dart' show CommonElements;
 import '../elements/entities.dart';
 import '../elements/types.dart';
 import '../universe/call_structure.dart' show CallStructure;
 import 'constructors.dart';
 import 'expressions.dart';
 
 /// Environment used for evaluating constant expressions.
 abstract class EvaluationEnvironment {
   CommonElements get commonElements;
 
   /// Read environments string passed in using the '-Dname=value' option.
   String readFromEnvironment(String name);
 
   /// Returns the [ConstantExpression] for the value of the constant [local].
-  ConstantExpression getLocalConstant(Local local);
+  ConstantExpression getLocalConstant(covariant Local local);
 
   /// Returns the [ConstantExpression] for the value of the constant [field].
-  ConstantExpression getFieldConstant(FieldEntity field);
+  ConstantExpression getFieldConstant(covariant FieldEntity field);
 
   /// Returns the [ConstantConstructor] corresponding to the constant
   /// [constructor].
-  ConstantConstructor getConstructorConstant(ConstructorEntity constructor);
+  ConstantConstructor getConstructorConstant(
+      covariant ConstructorEntity constructor);
 
   /// Performs the substitution of the type arguments of [target] for their
   /// corresponding type variables in [type].
-  InterfaceType substByContext(InterfaceType base, InterfaceType target);
+  InterfaceType substByContext(
+      covariant InterfaceType base, covariant InterfaceType target);
 }
 
 /// The normalized arguments passed to a const constructor computed from the
 /// actual [arguments] and the [defaultValues] of the called construrctor.
 class NormalizedArguments {
   final Map<dynamic /*int|String*/, ConstantExpression> defaultValues;
   final CallStructure callStructure;
   final List<ConstantExpression> arguments;
 
   NormalizedArguments(this.defaultValues, this.callStructure, this.arguments);
@@ skipping 63 matching lines @@
       if (needsComma) {
         sb.write(',');
       }
       sb.write(value.toStructuredText());
       needsComma = true;
     });
     sb.write(']]');
     return sb.toString();
   }
 }