Report HintCode.UNUSED_FIELD for fields which are referenced in constructor field initializers.

pkg/analyzer/test/generated/hint_code_test.dart

Index: pkg/analyzer/test/generated/hint_code_test.dart
diff --git a/pkg/analyzer/test/generated/hint_code_test.dart b/pkg/analyzer/test/generated/hint_code_test.dart
index 39752705c06ccf3780e8a592c3452bb3a52d2117..14b46d7805634829eea997aa4ec82d2173a14440 100644
--- a/pkg/analyzer/test/generated/hint_code_test.dart
+++ b/pkg/analyzer/test/generated/hint_code_test.dart
@@ -2886,6 +2886,30 @@ class A {
     verify([source]);
   }
 
+  void test_unusedField_notUsed_constructorFieldInitializers() {
+    enableUnusedElement = true;
+    Source source = addSource(r'''
+class A {
+  int _f;
+  A() : _f = 0;
+}''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.UNUSED_FIELD]);
+    verify([source]);
+  }
+
+  void test_unusedField_notUsed_fieldFormalParameter() {
+    enableUnusedElement = true;
+    Source source = addSource(r'''
+class A {
+  int _f;
+  A(this._f);
+}''');
+    computeLibrarySourceErrors(source);
+    assertErrors(source, [HintCode.UNUSED_FIELD]);
+    verify([source]);
+  }
+
   void test_unusedField_notUsed_noReference() {
     enableUnusedElement = true;
     Source source = addSource(r'''