add deprecated_consistency (#2451)

* add deprecated_consistency

* handle null field

* address review comments

* address review comments

example/all.yaml

@@ -59,6 +59,7 @@ linter:
     - constant_identifier_names
     - control_flow_in_finally
     - curly_braces_in_flow_control_structures
+    - deprecated_consistency
     - diagnostic_describe_all_properties
     - directives_ordering
     - do_not_use_environment

lib/src/rules.dart

@@ -60,6 +60,7 @@ import 'rules/comment_references.dart';
 import 'rules/constant_identifier_names.dart';
 import 'rules/control_flow_in_finally.dart';
 import 'rules/curly_braces_in_flow_control_structures.dart';
+import 'rules/deprecated_consistency.dart';
 import 'rules/diagnostic_describe_all_properties.dart';
 import 'rules/directives_ordering.dart';
 import 'rules/do_not_use_environment.dart';
@@ -246,6 +247,7 @@ void registerLintRules() {
     ..register(ConstantIdentifierNames())
     ..register(ControlFlowInFinally())
     ..register(CurlyBracesInFlowControlStructures())
+    ..register(DeprecatedConsistency())
     ..register(DiagnosticsDescribeAllProperties())
     ..register(DirectivesOrdering())
     ..register(DoNotUseEnvironment())

lib/src/rules/deprecated_consistency.dart

@@ -0,0 +1,97 @@
+// Copyright (c) 2021, 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.
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:analyzer/dart/element/element.dart';
+
+import '../analyzer.dart';
+
+const _desc = r'Missing deprecated annotation.';
+
+const _details = r'''
+
+Do apply `@Deprecated()` consistently:
+
+- if a class is deprecated, its constructors should also be deprecated.
+- if a field is deprecated, the constructor parameter pointing to it should also be deprecated.
+- if a constructor parameter pointing to a field is deprecated, the field should also be deprecated.
+
+**BAD:**
+```
+@deprecated
+class A {
+  A();
+}
+
+class B {
+  B({this.field});
+  @deprecated
+  Object field;
+}
+```
+
+**GOOD:**
+```
+@deprecated
+class A {
+  @deprecated
+  A();
+}
+
+class B {
+  B({@deprecated this.field});
+  @deprecated
+  Object field;
+}
+```
+
+''';
+
+class DeprecatedConsistency extends LintRule implements NodeLintRule {
+  DeprecatedConsistency()
+      : super(
+          name: 'deprecated_consistency',
+          description: _desc,
+          details: _details,
+          group: Group.style,
+        );
+
+  @override
+  void registerNodeProcessors(
+      NodeLintRegistry registry, LinterContext context) {
+    final visitor = _Visitor(this);
+    registry.addConstructorDeclaration(this, visitor);
+    registry.addFieldFormalParameter(this, visitor);
+  }
+}
+
+class _Visitor extends SimpleAstVisitor<void> {
+  final LintRule rule;
+
+  _Visitor(this.rule);
+
+  @override
+  void visitConstructorDeclaration(ConstructorDeclaration node) {
+    var constructorElement = node.declaredElement;
+    if (constructorElement.enclosingElement.hasDeprecated &&
+        !constructorElement.hasDeprecated) {
+      rule.reportLint(node);
+    }
+  }
+
+  @override
+  void visitFieldFormalParameter(FieldFormalParameter node) {
+    var declaredElement = node.declaredElement as FieldFormalParameterElement;
+    var field = declaredElement.field;
+    if (field == null) return;
+
+    if (field.hasDeprecated && !declaredElement.hasDeprecated) {
+      rule.reportLint(node);
+    }
+    if (!field.hasDeprecated && declaredElement.hasDeprecated) {
+      rule.reportLintForOffset(field.nameOffset, field.nameLength);
+    }
+  }
+}

test/rules/deprecated_consistency.dart

@@ -0,0 +1,26 @@
+// Copyright (c) 2021, 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.
+
+// test w/ `pub run test -N deprecated_consistency`
+
+@deprecated
+class A {
+  A.ko(); // LINT
+  @deprecated
+  A.ok(); // OK
+}
+
+class B {
+  B.ko({this.field = 0}); // LINT
+  B.ok({@deprecated this.field = 0}); // OK
+
+  @deprecated
+  Object field;
+}
+
+class C {
+  C({@deprecated this.field = 0}); // OK
+
+  Object field; // LINT
+}