From e688981385bd589a915d6af3cf1534a3a3a7a3e4 Mon Sep 17 00:00:00 2001
From: Nate Biggs <natebiggs@google.com>
Date: Wed, 21 May 2025 17:49:22 -0700
Subject: [PATCH] [ddc] Fix capture issue with temp names within async scopes.

`needsCapture` will ensure that any variables used within an async scope get included in the 'asyncScope' object that's created for that scope.

The variables used to lower Dart late variables in particular get emitted separately. But they can still be used across async scopes so they need the special capture logic as well.

Bug: https://github.com/dart-lang/sdk/issues/60748
Change-Id: I2486fce41f88f186fd799029c2cc59635f7ad8f5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/429780
Reviewed-by: Nicholas Shahan <nshahan@google.com>
Commit-Queue: Nate Biggs <natebiggs@google.com>
---
 pkg/dev_compiler/lib/src/kernel/compiler.dart |  3 +-
 .../lib/src/kernel/compiler_new.dart          |  3 +-
 tests/web/regress/issue/60748_test.dart       | 33 +++++++++++++++++++
 3 files changed, 37 insertions(+), 2 deletions(-)
 create mode 100644 tests/web/regress/issue/60748_test.dart

diff --git a/pkg/dev_compiler/lib/src/kernel/compiler.dart b/pkg/dev_compiler/lib/src/kernel/compiler.dart
index 157f42277eb..d1ba90a179c 100644
--- a/pkg/dev_compiler/lib/src/kernel/compiler.dart
+++ b/pkg/dev_compiler/lib/src/kernel/compiler.dart
@@ -4918,7 +4918,8 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
     if (_isTemporaryVariable(v)) {
       var name = _debuggerFriendlyTemporaryVariableName(v);
       name ??= 't\$${_tempVariables.length}';
-      return _tempVariables.putIfAbsent(v, () => _emitScopedId(name!));
+      return _tempVariables.putIfAbsent(
+          v, () => _emitScopedId(name!, needsCapture: true));
     }
     var name = v.name!;
     if (isLateLoweredLocal(v)) {
diff --git a/pkg/dev_compiler/lib/src/kernel/compiler_new.dart b/pkg/dev_compiler/lib/src/kernel/compiler_new.dart
index dc0bda3e36f..12dc2e2b7aa 100644
--- a/pkg/dev_compiler/lib/src/kernel/compiler_new.dart
+++ b/pkg/dev_compiler/lib/src/kernel/compiler_new.dart
@@ -5403,7 +5403,8 @@ class LibraryCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
     if (_isTemporaryVariable(v)) {
       var name = _debuggerFriendlyTemporaryVariableName(v);
       name ??= 't\$${_tempVariables.length}';
-      return _tempVariables.putIfAbsent(v, () => _emitScopedId(name!));
+      return _tempVariables.putIfAbsent(
+          v, () => _emitScopedId(name!, needsCapture: true));
     }
     var name = v.name!;
     if (isLateLoweredLocal(v)) {
diff --git a/tests/web/regress/issue/60748_test.dart b/tests/web/regress/issue/60748_test.dart
new file mode 100644
index 00000000000..6874f9d10a7
--- /dev/null
+++ b/tests/web/regress/issue/60748_test.dart
@@ -0,0 +1,33 @@
+// Copyright (c) 2025, 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:expect/async_helper.dart';
+import 'package:expect/expect.dart';
+
+Future<void> main() async {
+  asyncStart();
+  List<Object Function()> callbacks = [];
+  List<int> expectedHashCodes = [];
+
+  void save(Object o) {
+    expectedHashCodes.add(o.hashCode);
+  }
+
+  void check(Object o, int i) {
+    Expect.equals(expectedHashCodes[i], o.hashCode);
+  }
+
+  for (int i = 0; i < 3; i++) {
+    late Object o = Object();
+    o;
+    Object record() => o;
+    callbacks.add(record);
+    save(record());
+  }
+
+  for (int i = callbacks.length - 1; i >= 0; i--) {
+    check(callbacks[i](), i);
+  }
+  asyncEnd();
+}