Code completion for record fields.

Change-Id: I03134b2c0c7fac2595c23b00f9d13b5e344d15a9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/256961
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/lib/src/services/completion/dart/suggestion_builder.dart

@@ -937,6 +937,36 @@ class SuggestionBuilder {
     );
   }
 
+  void suggestRecordField({
+    required RecordTypeField field,
+    required String name,
+  }) {
+    final type = field.type;
+    final featureComputer = request.featureComputer;
+    final contextType =
+        featureComputer.contextTypeFeature(request.contextType, type);
+    final relevance = _computeRelevance(
+      contextType: contextType,
+    );
+
+    final returnType = field.type.getDisplayString(
+      withNullability: _isNonNullableByDefault,
+    );
+
+    _addSuggestion(
+      CompletionSuggestion(
+        CompletionSuggestionKind.IDENTIFIER,
+        relevance,
+        name,
+        name.length,
+        0,
+        false,
+        false,
+        returnType: returnType,
+      ),
+    );
+  }
+
   /// Add a suggestion for a static field declared within a class or extension.
   /// If the field is synthetic, add the corresponding getter instead.
   ///

pkg/analysis_server/lib/src/services/completion/dart/type_member_contributor.dart

@@ -10,6 +10,7 @@ import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer_plugin/src/utilities/visitors/local_declaration_visitor.dart';
+import 'package:collection/collection.dart';
 
 /// A contributor that produces suggestions based on the instance members of a
 /// given type, whether declared by that type directly or inherited from a
@@ -89,6 +90,24 @@ class TypeMemberContributor extends DartCompletionContributor {
       var memberBuilder = _SuggestionBuilder(request, builder);
       memberBuilder.buildSuggestions(type,
           mixins: mixins, superclassConstraints: superclassConstraints);
+    } else if (type is RecordType) {
+      _suggestFromRecordType(type);
+    }
+  }
+
+  void _suggestFromRecordType(RecordType type) {
+    type.positionalFields.forEachIndexed((index, field) {
+      builder.suggestRecordField(
+        field: field,
+        name: '\$$index',
+      );
+    });
+
+    for (final field in type.namedFields) {
+      builder.suggestRecordField(
+        field: field,
+        name: field.name,
+      );
     }
   }
 }

pkg/analysis_server/test/services/completion/dart/completion_check.dart

@@ -269,6 +269,11 @@ extension CompletionSuggestionExtension
     element.isNotNull.kind.isParameter;
   }
 
+  void get isRecordField {
+    kind.isIdentifier;
+    element.isNull;
+  }
+
   void get isSetter {
     kind.isIdentifier;
     element.isNotNull.kind.isSetter;

pkg/analysis_server/test/services/completion/dart/declaration/record_type_test.dart

@@ -0,0 +1,95 @@
+// Copyright (c) 2022, 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_utilities/check/check.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import '../../../../client/completion_driver_test.dart';
+import '../completion_check.dart';
+
+void main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(RecordTypeTest1);
+    defineReflectiveTests(RecordTypeTest2);
+  });
+}
+
+@reflectiveTest
+class RecordTypeTest1 extends AbstractCompletionDriverTest
+    with RecordTypeTestCases {
+  @override
+  TestingCompletionProtocol get protocol => TestingCompletionProtocol.version1;
+}
+
+@reflectiveTest
+class RecordTypeTest2 extends AbstractCompletionDriverTest
+    with RecordTypeTestCases {
+  @override
+  TestingCompletionProtocol get protocol => TestingCompletionProtocol.version2;
+}
+
+mixin RecordTypeTestCases on AbstractCompletionDriverTest {
+  Future<void> test_mixin() async {
+    var response = await getTestCodeSuggestions('''
+void f((int, {String foo02}) r) {
+  r.^
+}
+''');
+
+    check(response)
+      ..hasEmptyReplacement()
+      ..suggestions.matchesInAnyOrder([
+        (suggestion) => suggestion
+          ..completion.isEqualTo(r'$0')
+          ..isRecordField
+          ..returnType.isEqualTo('int'),
+        (suggestion) => suggestion
+          ..completion.isEqualTo(r'foo02')
+          ..isRecordField
+          ..returnType.isEqualTo('String'),
+      ]);
+  }
+
+  Future<void> test_named() async {
+    var response = await getTestCodeSuggestions('''
+void f(({int foo01, String foo02}) r) {
+  r.^
+}
+''');
+
+    check(response)
+      ..hasEmptyReplacement()
+      ..suggestions.matchesInAnyOrder([
+        (suggestion) => suggestion
+          ..completion.isEqualTo(r'foo01')
+          ..isRecordField
+          ..returnType.isEqualTo('int'),
+        (suggestion) => suggestion
+          ..completion.isEqualTo(r'foo02')
+          ..isRecordField
+          ..returnType.isEqualTo('String'),
+      ]);
+  }
+
+  Future<void> test_positional() async {
+    var response = await getTestCodeSuggestions('''
+void f((int, String) r) {
+  r.^
+}
+''');
+
+    check(response)
+      ..hasEmptyReplacement()
+      ..suggestions.matchesInAnyOrder([
+        (suggestion) => suggestion
+          ..completion.isEqualTo(r'$0')
+          ..isRecordField
+          ..returnType.isEqualTo('int'),
+        (suggestion) => suggestion
+          ..completion.isEqualTo(r'$1')
+          ..isRecordField
+          ..returnType.isEqualTo('String'),
+      ]);
+  }
+}

pkg/analysis_server/test/services/completion/dart/declaration/test_all.dart

@@ -7,6 +7,7 @@ import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'class_test.dart' as class_;
 import 'enum_test.dart' as enum_;
 import 'library_test.dart' as library_;
+import 'record_type_test.dart' as record_type;
 
 /// Tests suggestions produced for various kinds of declarations.
 void main() {
@@ -14,5 +15,6 @@ void main() {
     class_.main();
     enum_.main();
     library_.main();
+    record_type.main();
   });
 }

pkg/analysis_server/test/services/completion/dart/relevance/instance_member_test.dart

@@ -29,7 +29,7 @@ class InstanceMemberTest2 extends CompletionRelevanceTest
 }
 
 mixin InstanceMemberTestCases on CompletionRelevanceTest {
-  Future<void> test_contextType() async {
+  Future<void> test_contextType_interfaceType_method() async {
     await addTestFile(r'''
 class A {}
 class B extends A {}
@@ -56,6 +56,48 @@ void g(E e) {
     ]);
   }
 
+  Future<void> test_contextType_recordType_named() async {
+    await addTestFile(r'''
+class A {}
+class B extends A {}
+class C extends B {}
+class D {}
+
+void f(B _) {}
+
+void g(({A foo01, B foo02, C foo03, D foo04}) r) {
+  f(r.^);
+}
+''');
+    assertOrder([
+      suggestionWith(completion: r'foo02'), // same
+      suggestionWith(completion: r'foo03'), // subtype
+      suggestionWith(completion: r'foo04'), // unrelated
+      suggestionWith(completion: r'foo01'), // supertype
+    ]);
+  }
+
+  Future<void> test_contextType_recordType_positional() async {
+    await addTestFile(r'''
+class A {}
+class B extends A {}
+class C extends B {}
+class D {}
+
+void f(B _) {}
+
+void g((A, B, C, D) r) {
+  f(r.^);
+}
+''');
+    assertOrder([
+      suggestionWith(completion: r'$1'), // same
+      suggestionWith(completion: r'$2'), // subtype
+      suggestionWith(completion: r'$3'), // unrelated
+      suggestionWith(completion: r'$0'), // supertype
+    ]);
+  }
+
   Future<void> test_elementKind() async {
     await addTestFile('''
 class A {