Avoid using FunctionSignature in builder_kernel

pkg/compiler/lib/src/closure.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.
 
 library closureToClassMapper;
 
 import 'common/names.dart' show Identifiers;
 import 'common/resolution.dart' show ParsingContext, Resolution;
 import 'common/tasks.dart' show CompilerTask;
 import 'common.dart';
 import 'compiler.dart' show Compiler;
 import 'constants/expressions.dart';
-import 'elements/resolution_types.dart';
 import 'elements/elements.dart';
 import 'elements/entities.dart';
 import 'elements/entity_utils.dart' as utils;
 import 'elements/modelx.dart'
     show BaseFunctionElementX, ClassElementX, ElementX;
+import 'elements/resolution_types.dart';
+import 'elements/types.dart';
 import 'elements/visitor.dart' show ElementVisitor;
 import 'js_backend/js_backend.dart' show JavaScriptBackend;
 import 'resolution/tree_elements.dart' show TreeElements;
 import 'package:front_end/src/fasta/scanner.dart' show Token;
 import 'tree/tree.dart';
 import 'util/util.dart';
 import 'world.dart' show ClosedWorldRefiner;
 
 abstract class ClosureClassMaps {
   ClosureClassMap getMemberMap(MemberEntity member);
@@ skipping 731 matching lines @@
       }
     } else if (variable is LocalParameterElement &&
         variable.functionDeclaration.asyncMarker == AsyncMarker.SYNC_STAR) {
       // Parameters in a sync* function are shared between each Iterator created
       // by the Iterable returned by the function, therefore they must be boxed.
       closureData.variablesUsedInTryOrGenerator.add(variable);
     }
   }
 
   void useTypeVariableAsLocal(ResolutionTypeVariableType typeVariable) {
-    useLocal(new TypeVariableLocal(typeVariable, outermostElement));
+    useLocal(new TypeVariableLocal(
+        typeVariable, outermostElement, outermostElement.memberContext));
   }
 
   void declareLocal(LocalVariableElement element) {
     scopeVariables.add(element);
   }
 
   void registerNeedsThis() {
     if (closureData.thisLocal != null) {
       useLocal(closureData.thisLocal);
     }
@@ skipping 429 matching lines @@
     // An `await for` loop is enclosed in an implicit try-finally.
     bool oldInTryStatement = inTryStatement;
     inTryStatement = true;
     visitLoop(node);
     inTryStatement = oldInTryStatement;
   }
 }
 
 /// A type variable as a local variable.
 class TypeVariableLocal implements Local {
-  final ResolutionTypeVariableType typeVariable;
-  final ExecutableElement executableContext;
+  final TypeVariableType typeVariable;
+  final Entity executableContext;
+  final MemberEntity memberContext;
 
-  TypeVariableLocal(this.typeVariable, this.executableContext);
+  TypeVariableLocal(
+      this.typeVariable, this.executableContext, this.memberContext);
 
-  @override
-  MemberElement get memberContext => executableContext.memberContext;
-
-  String get name => typeVariable.name;
+  String get name => typeVariable.element.name;
 
   int get hashCode => typeVariable.hashCode;
 
   bool operator ==(other) {
     if (other is! TypeVariableLocal) return false;
     return typeVariable == other.typeVariable;
   }
 }
 
 ///
 /// Move the below classes to a JS model eventually.
 ///
 abstract class JSEntity implements Entity {
   Entity get declaredEntity;
 }
 
 abstract class PrivatelyNamedJSEntity implements JSEntity {
   Entity get rootOfScope;
 }