Fix for updating HINTS during incremental resolution with TM.

pkg/analyzer/test/generated/incremental_resolver_test.dart

Index: pkg/analyzer/test/generated/incremental_resolver_test.dart
diff --git a/pkg/analyzer/test/generated/incremental_resolver_test.dart b/pkg/analyzer/test/generated/incremental_resolver_test.dart
index a60941bb8bacaaad3e93e29e739920b94655480c..50c51babc20bd9f2cf6d2daf400432185b14d1e8 100644
--- a/pkg/analyzer/test/generated/incremental_resolver_test.dart
+++ b/pkg/analyzer/test/generated/incremental_resolver_test.dart
@@ -3435,11 +3435,19 @@ class A {
 ''');
   }
 
+  @override
   void setUp() {
+    AnalysisEngine.instance.useTaskModel = true;
     super.setUp();
     _resetWithIncremental(true);
   }
 
+  @override
+  void tearDown() {
+    super.tearDown();
+    AnalysisEngine.instance.useTaskModel = false;
+  }
+
   void test_computeConstants() {
     _resolveUnit(r'''
 int f() => 0;
@@ -4160,6 +4168,28 @@ class A {
 ''');
   }
 
+  void test_true_todoHint() {
+    _resolveUnit(r'''
+main() {
+  print(1);
+}
+foo() {
+ // TODO
+}
+''');
+    List<AnalysisError> oldErrors = analysisContext.computeErrors(source);
+    _updateAndValidate(r'''
+main() {
+  print(2);
+}
+foo() {
+ // TODO
+}
+''');
+    List<AnalysisError> newErrors = analysisContext.computeErrors(source);
+    _assertEqualErrors(newErrors, oldErrors);
+  }
+
   void test_unusedHint_add_wasUsedOnlyInPart() {
     Source partSource = addNamedSource(
         '/my_unit.dart',