fix #26414, infer return types of local functions

pkg/analyzer/test/generated/strong_mode_test.dart

 // Copyright (c) 2016, 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.test.generated.strong_mode_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/element.dart';
@@ skipping 1727 matching lines @@
   }
 
   void test_genericMethod_nestedFunctions() {
     resolveTestUnit(r'''
 /*=S*/ f/*<S>*/(/*=S*/ x) {
   g/*<S>*/(/*=S*/ x) => f;
   return null;
 }
 ''');
     expectIdentifierType('f', '<S>(S) → S');
-    expectIdentifierType('g', '<S>(S) → dynamic');
+    expectIdentifierType('g', '<S>(S) → <S>(S) → S');
   }
 
   void test_genericMethod_override() {
     resolveTestUnit(r'''
 class C {
   /*=T*/ f/*<T>*/(/*=T*/ x) => null;
 }
 class D extends C {
   /*=T*/ f/*<T>*/(/*=T*/ x) => null; // from D
 }
@@ skipping 549 matching lines @@
 main() {
   var v = x;
   v; // marker
 }
 int x = 3;
 ''';
     assertPropagatedAssignedType(code, typeProvider.intType, null);
     assertTypeOfMarkedExpression(code, typeProvider.intType, null);
   }
 }