add fix for use_rethrow

See: https://github.com/dart-lang/linter/issues/1374.

Change-Id: I7e79ad37681afdbd94d7968451a768e74217578e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/95708
Commit-Queue: Phil Quitslund <pquitslund@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

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

@@ -297,4 +297,6 @@ class DartFixKind {
       'USE_NOT_EQ_NULL', 50, "Use != null instead of 'is! Null'",
       appliedTogetherMessage:
           "Use != null instead of 'is! Null' everywhere in file");
+  static const USE_RETHROW =
+      const FixKind('USE_RETHROW', 50, "Replace throw with rethrow");
 }

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

@@ -625,6 +625,9 @@ class FixProcessor {
       if (name == LintNames.unnecessary_this) {
         await _addFix_removeThisExpression();
       }
+      if (name == LintNames.use_rethrow_when_possible) {
+        await _addFix_replaceWithRethrow();
+      }
     }
     // done
     return fixes;
@@ -3224,6 +3227,16 @@ class FixProcessor {
     }
   }
 
+  Future<void> _addFix_replaceWithRethrow() async {
+    if (coveredNode is ThrowExpression) {
+      var changeBuilder = _newDartChangeBuilder();
+      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
+        builder.addSimpleReplacement(range.node(coveredNode), 'rethrow');
+      });
+      _addFixFromBuilder(changeBuilder, DartFixKind.USE_RETHROW);
+    }
+  }
+
   Future<void> _addFix_replaceWithIdentifier() async {
     // TODO(brianwilkerson) Determine whether this await is necessary.
     await null;
@@ -4329,6 +4342,7 @@ class LintNames {
   static const String unnecessary_new = 'unnecessary_new';
   static const String unnecessary_override = 'unnecessary_override';
   static const String unnecessary_this = 'unnecessary_this';
+  static const String use_rethrow_when_possible = 'use_rethrow_when_possible';
 }
 
 /**

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

@@ -0,0 +1,42 @@
+// Copyright (c) 2019, 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:analysis_server/src/services/correction/fix.dart';
+import 'package:analysis_server/src/services/correction/fix_internal.dart';
+import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import 'fix_processor.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(UseRethrowTest);
+  });
+}
+
+@reflectiveTest
+class UseRethrowTest extends FixProcessorLintTest {
+  @override
+  FixKind get kind => DartFixKind.USE_RETHROW;
+
+  @override
+  String get lintCode => LintNames.use_rethrow_when_possible;
+
+  test_rethrow() async {
+    await resolveTestUnit('''
+void bad1() {
+  try {} catch (e) {
+    throw/*LINT*/ e;
+  }
+}
+''');
+    await assertHasFix('''
+void bad1() {
+  try {} catch (e) {
+    rethrow;
+  }
+}
+''');
+  }
+}