fix generic function expressions, part of #25175

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/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
@@ skipping 3082 matching lines @@
       Block enclosingBlock = node.getAncestor((node) => node is Block);
       if (enclosingBlock != null) {
         int functionEnd = node.offset + node.length;
         int blockEnd = enclosingBlock.offset + enclosingBlock.length;
         element.setVisibleRange(functionEnd, blockEnd - functionEnd - 1);
       }
     }
     if (_functionTypesToFix != null) {
       _functionTypesToFix.add(element);
     } else {
-      // TODO(jmesserly): for local functions inside of top-level generic
-      // functions, this is probably not right. The function type should be set
-      // after the enclosingElement is set, otherwise we won't be able to
-      // substitute those type parameters later.
       element.type = new FunctionTypeImpl(element);
     }
     element.hasImplicitReturnType = true;
     _currentHolder.addFunction(element);
     node.element = element;
     holder.validate();
     return null;
   }
 
   @override
@@ skipping 10440 matching lines @@
     nonFields.add(node);
     return null;
   }
 
   @override
   Object visitNode(AstNode node) => node.accept(TypeResolverVisitor_this);
 
   @override
   Object visitWithClause(WithClause node) => null;
 }