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

pkg/analyzer/test/dart/ast/ast_test.dart

Index: pkg/analyzer/test/dart/ast/ast_test.dart
diff --git a/pkg/analyzer/test/dart/ast/ast_test.dart b/pkg/analyzer/test/dart/ast/ast_test.dart
index 35ff9a9029630b4976faca25eb4115b5f920c90e..122a93e014a19682e7df00e9835791785a2825c4 100644
--- a/pkg/analyzer/test/dart/ast/ast_test.dart
+++ b/pkg/analyzer/test/dart/ast/ast_test.dart
@@ -592,6 +592,13 @@ class SimpleIdentifierTest extends ParserTestCase {
     }
   }
 
+  void test_inGetterContext_constructorFieldInitializer() {
+    ConstructorFieldInitializer initializer = AstFactory
+        .constructorFieldInitializer(false, 'f', AstFactory.integer(0));
+    SimpleIdentifier identifier = initializer.fieldName;
+    expect(identifier.inGetterContext(), isFalse);
+  }
+
   void test_inGetterContext_forEachLoop() {
     SimpleIdentifier identifier = AstFactory.identifier3("a");
     Expression iterator = AstFactory.listLiteral();