scope debug property assist to Diagnosticables

Fixes: #42783

Change-Id: Ied9b0fa04e0f99b4d5b4604c72696b5cfaec737d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/155501
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

Author: pq

pkg/analysis_server/lib/src/services/correction/dart/add_diagnostic_property_reference.dart

@@ -27,6 +27,13 @@ class AddDiagnosticPropertyReference extends CorrectionProducer {
     if (node is! SimpleIdentifier) {
       return;
     }
+
+    var classDeclaration = node.thisOrAncestorOfType<ClassOrMixinDeclaration>();
+    if (classDeclaration == null ||
+        !flutter.isDiagnosticable(classDeclaration.declaredElement.thisType)) {
+      return;
+    }
+
     SimpleIdentifier name = node;
     final parent = node.parent;
 
@@ -98,10 +105,6 @@ class AddDiagnosticPropertyReference extends CorrectionProducer {
       builder.writeln("$constructorName('${name.name}', ${name.name}));");
     }
 
-    final classDeclaration = parent.thisOrAncestorOfType<ClassDeclaration>();
-    if (classDeclaration == null) {
-      return;
-    }
     final debugFillProperties =
         classDeclaration.getMethod('debugFillProperties');
     if (debugFillProperties == null) {

pkg/analysis_server/lib/src/utilities/flutter.dart

@@ -36,6 +36,9 @@ class Flutter {
   final Uri _uriContainer = Uri.parse(
     'package:flutter/src/widgets/container.dart',
   );
+  final Uri _uriDiagnostics = Uri.parse(
+    'package:flutter/src/foundation/diagnostics.dart',
+  );
   final Uri _uriEdgeInsets = Uri.parse(
     'package:flutter/src/painting/edge_insets.dart',
   );
@@ -337,6 +340,35 @@ class Flutter {
     return isColorElement(type.element);
   }
 
+  /// Return `true` if the given [type] is the flutter mixin `Diagnosticable`
+  /// or its subtype.
+  bool isDiagnosticable(DartType type) {
+    if (type is! InterfaceType) {
+      return false;
+    }
+
+    bool isDiagnosticableElement(ClassElement element) {
+      if (element == null) {
+        return false;
+      }
+
+      bool isExactDiagnosticable(ClassElement element) =>
+          element?.name == 'Diagnosticable' &&
+          element.source.uri == _uriDiagnostics;
+      if (isExactDiagnosticable(element)) {
+        return true;
+      }
+      for (var type in element.allSupertypes) {
+        if (isExactDiagnosticable(type.element)) {
+          return true;
+        }
+      }
+      return false;
+    }
+
+    return isDiagnosticableElement(type.element);
+  }
+
   /// Return `true` if the [element] is the Flutter class `Alignment`.
   bool isExactAlignment(ClassElement element) {
     return _isExactWidget(element, 'Alignment', _uriAlignment);
@@ -432,8 +464,8 @@ class Flutter {
         isWidgetType(type.typeArguments[0]);
   }
 
-  /// Return `true` if the given [type] is the dart.ui class `Color`, or its
-  /// subtype.
+  /// Return `true` if the given [type] is the vector_math_64 class `Matrix4`,
+  /// or its subtype.
   bool isMatrix4(DartType type) {
     if (type is! InterfaceType) {
       return false;

pkg/analysis_server/test/mock_packages/flutter/lib/src/foundation/diagnostics.dart

@@ -2,10 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-abstract class Diagnosticable with DiagnosticableMixin {}
-
+///// todo (pq): remove when linter 0.1.118 is integrated.
 mixin DiagnosticableMixin {}
 
+mixin Diagnosticable {}
+
+abstract class DiagnosticableTree with Diagnosticable {}
+
 class DiagnosticPropertiesBuilder {
   void add(DiagnosticsNode property) {}
 }

pkg/analysis_server/test/mock_packages/flutter/lib/src/widgets/framework.dart

@@ -47,7 +47,7 @@ abstract class StatelessWidget extends Widget {
   Widget build(BuildContext context) => null;
 }
 
-class Widget {
+class Widget extends DiagnosticableTree {
   final Key key;
 
   const Widget({this.key});

pkg/analysis_server/test/src/services/correction/assist/add_diagnostic_property_reference_test.dart

@@ -21,8 +21,11 @@ class AddDiagnosticPropertyReferenceTest extends AssistProcessorTest {
 
   /// Full coverage in fix/add_diagnostic_property_reference_test.dart
   Future<void> test_boolField_debugFillProperties() async {
-    verifyNoTestUnitErrors = false;
+    addFlutterPackage();
     await resolveTestUnit('''
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
+
 class W extends Widget {
   bool /*caret*/property;
   @override
@@ -32,6 +35,9 @@ class W extends Widget {
 }
 ''');
     await assertHasAssist('''
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
+
 class W extends Widget {
   bool property;
   @override
@@ -49,6 +55,16 @@ class W extends Widget {
 mixin MyMixin {
   String get foo/*caret*/() {}
 }
+''');
+    await assertNoAssist();
+  }
+
+  Future<void> test_notAvailable_outsideDiagnosticable() async {
+    addFlutterPackage();
+    await resolveTestUnit('''
+class C {
+  String get f/*caret*/ => null;
+}
 ''');
     await assertNoAssist();
   }

pkg/analysis_server/test/src/services/correction/fix/add_diagnostic_property_reference_test.dart

@@ -31,6 +31,7 @@ class AddDiagnosticPropertyReferenceTest extends FixProcessorLintTest {
   }
 
   Future<void> test_boolField() async {
+    // todo(pq): when linter 0.1.118 is integrated, update DiagnosticableMixin to Diagnosticable
     await resolveTestUnit('''
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';