Mark FunctionExpression elements as used in DeclarationResolver.

pkg/analyzer/lib/src/generated/resolver.dart

 // Copyright (c) 2014, 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 analyzer.src.generated.resolver;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
@@ skipping 2284 matching lines @@
     } finally {
       _enclosingExecutable = outerExecutable;
     }
   }
 
   @override
   Object visitFunctionExpression(FunctionExpression node) {
     if (node.parent is! FunctionDeclaration) {
       FunctionElement element = _findAtOffset(
           _enclosingExecutable.functions, node, node.beginToken.offset);
+      _expectedElements.remove(element);
       node.element = element;
     }
     ExecutableElement outerExecutable = _enclosingExecutable;
     try {
       _enclosingExecutable = node.element;
       return super.visitFunctionExpression(node);
     } finally {
       _enclosingExecutable = outerExecutable;
     }
   }
@@ skipping 10417 matching lines @@
     nonFields.add(node);
     return null;
   }
 
   @override
   Object visitNode(AstNode node) => node.accept(TypeResolverVisitor_this);
 
   @override
   Object visitWithClause(WithClause node) => null;
 }