Flatten inferrer implementation

pkg/compiler/lib/src/inferrer/node_tracer.dart

 // Copyright (c) 2013, 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 compiler.src.inferrer.node_tracer;
 
 import '../common/names.dart' show Identifiers;
 import '../compiler.dart' show Compiler;
 import '../elements/elements.dart';
 import '../types/types.dart' show ContainerTypeMask, MapTypeMask;
 import '../util/util.dart' show Setlet;
 import 'debug.dart' as debug;
-import 'type_graph_inferrer.dart' show TypeGraphInferrerEngine;
+import 'inferrer_engine.dart';
 import 'type_graph_nodes.dart';
 
 // A set of selectors we know do not escape the elements inside the
 // list.
 Set<String> doesNotEscapeListSet = new Set<String>.from(const <String>[
   // From Object.
   '==',
   'hashCode',
   'toString',
   'noSuchMethod',
@@ skipping 41 matching lines @@
   'length',
   'clear',
   'containsKey',
   'containsValue',
   '[]=',
   // [keys] only allows key values to escape, which we do not track.
   'keys'
 ]);
 
 /// Common logic to trace a value through the type inference graph nodes.
-abstract class TracerVisitor<T extends TypeInformation>
-    implements TypeInformationVisitor {
-  final T tracedType;
-  final TypeGraphInferrerEngine inferrer;
+abstract class TracerVisitor implements TypeInformationVisitor {
+  final TypeInformation tracedType;
+  final InferrerEngine inferrer;
   final Compiler compiler;
 
   static const int MAX_ANALYSIS_COUNT = 16;
   final Setlet<Element> analyzedElements = new Setlet<Element>();
 
-  TracerVisitor(this.tracedType, TypeGraphInferrerEngine inferrer)
+  TracerVisitor(this.tracedType, InferrerEngine inferrer)
       : this.inferrer = inferrer,
         this.compiler = inferrer.compiler;
 
   // Work list that gets populated with [TypeInformation] that could
   // contain the container.
   final List<TypeInformation> workList = <TypeInformation>[];
 
   // Work list of lists to analyze after analyzing the users of a
   // [TypeInformation]. We know the [tracedType] has been stored in these
   // lists and we must check how it escapes from these lists.
@@ skipping 307 matching lines @@
     }
     if (isParameterOfListAddingMethod(info.element) ||
         isParameterOfMapAddingMethod(info.element)) {
       // These elements are being handled in
       // [visitDynamicCallSiteTypeInformation].
       return;
     }
     addNewEscapeInformation(info);
   }
 }