[DAS] Makes encapsulate field work with final

[email protected]

Fixes: #60154
Change-Id: I45c887169672e3cdbce4aea95000996c09e8123b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/410460
Reviewed-by: Konstantin Shcheglov <[email protected]>
Commit-Queue: Phil Quitslund <[email protected]>
Reviewed-by: Phil Quitslund <[email protected]>
Auto-Submit: Felipe Morschel <[email protected]>

Author: FMorschel

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

@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analysis_server/src/services/correction/assist.dart';
+import 'package:analysis_server/src/utilities/extensions/ast.dart';
 import 'package:analysis_server_plugin/edit/dart/correction_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element2.dart';
@@ -17,9 +18,8 @@ class EncapsulateField extends ResolvedCorrectionProducer {
 
   @override
   CorrectionApplicability get applicability =>
-          // TODO(applicability): comment on why.
-          CorrectionApplicability
-          .singleLocation;
+      // TODO(applicability): comment on why.
+      CorrectionApplicability.singleLocation;
 
   @override
   AssistKind get assistKind => DartAssistKind.ENCAPSULATE_FIELD;
@@ -40,10 +40,6 @@ class EncapsulateField extends ResolvedCorrectionProducer {
     if (variableList.keyword == null && variableList.type == null) {
       return;
     }
-    // not interesting for final
-    if (variableList.isFinal) {
-      return;
-    }
     // should have exactly one field
     var fields = variableList.variables;
     if (fields.length != 1) {
@@ -88,6 +84,16 @@ class EncapsulateField extends ResolvedCorrectionProducer {
       }
       // rename field
       builder.addSimpleReplacement(range.token(nameToken), '_$name');
+      // Write setter.
+      if (variableList.finalKeyword case var finalKeyword?) {
+        builder.addSimpleReplacement(
+          range.startStart(
+            finalKeyword,
+            variableList.type ?? variableList.variables.first,
+          ),
+          '',
+        );
+      }
 
       String fieldTypeCode;
       var type = fieldDeclaration.fields.type;
@@ -147,6 +153,9 @@ class EncapsulateField extends ResolvedCorrectionProducer {
         builder.write('  ${typeCode}get $name => _$name;');
 
         // Write setter.
+        if (variableList.isFinal) {
+          return;
+        }
         var overriddenSetters = inheritanceManager.getOverridden4(
           parentElement,
           Name(null, '$name='),

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

@@ -279,8 +279,7 @@ enum E {
   final int test = 42;
 }
 ''');
-    // Enums can have only final fields, and final fields cannot be encapsulated
-    // right now.
+    // Enums can have only final fields.
     await assertNoAssistAt('test = 42');
   }
 
@@ -300,7 +299,13 @@ class A {
   final int test = 42;
 }
 ''');
-    await assertNoAssistAt('test =');
+    await assertHasAssistAt('test =', '''
+class A {
+  int _test = 42;
+
+  int get test => _test;
+}
+''');
   }
 
   Future<void> test_hasType() async {