From 2b396dd95a60d7b62b8673ee2be3649b108808d0 Mon Sep 17 00:00:00 2001
From: Martin Kustermann <kustermann@google.com>
Date: Thu, 1 Feb 2024 11:38:58 +0000
Subject: [PATCH] [dart2wasm] Fix type substitution bug if records are involved

Fixes https://github.com/dart-lang/sdk/issues/54794

Change-Id: I13b4ae619fad7d7e00f4a17e199b85ebea4e6de7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/349680
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
---
 sdk/lib/_internal/wasm/lib/type.dart   | 10 ++++++++++
 tests/web/wasm/regress_54794_test.dart | 25 +++++++++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 tests/web/wasm/regress_54794_test.dart

diff --git a/sdk/lib/_internal/wasm/lib/type.dart b/sdk/lib/_internal/wasm/lib/type.dart
index c1de560c813..26c29c94a22 100644
--- a/sdk/lib/_internal/wasm/lib/type.dart
+++ b/sdk/lib/_internal/wasm/lib/type.dart
@@ -736,6 +736,16 @@ class _TypeUniverse {
       assert(rootFunction == null);
       return substituteInterfaceTypeParameter(
           type.as<_InterfaceTypeParameterType>(), substitutions);
+    } else if (type.isRecord) {
+      final recordType = type.as<_RecordType>();
+      final fieldTypes = WasmArray<_Type>.filled(
+          recordType.fieldTypes.length, _literal<dynamic>());
+      for (int i = 0; i < recordType.fieldTypes.length; i++) {
+        fieldTypes[i] = substituteTypeArgument(
+            recordType.fieldTypes[i], substitutions, rootFunction);
+      }
+      return _RecordType(
+          recordType.names, fieldTypes, recordType.isDeclaredNullable);
     } else if (type.isFunction) {
       _FunctionType functionType = type.as<_FunctionType>();
       bool isRoot = identical(type, rootFunction);
diff --git a/tests/web/wasm/regress_54794_test.dart b/tests/web/wasm/regress_54794_test.dart
new file mode 100644
index 00000000000..4737dacb501
--- /dev/null
+++ b/tests/web/wasm/regress_54794_test.dart
@@ -0,0 +1,25 @@
+// Copyright (c) 2024, 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/expect.dart';
+
+main() {
+  final dynamic object = int.parse('1') == 1 ? Sub<int, String>() : 1;
+
+  Expect.isTrue(isBase<dynamic>(object));
+  Expect.isTrue(isBase<Object>(object));
+  Expect.isTrue(isBase<(dynamic, dynamic)>(object));
+  Expect.isTrue(isBase<(int, dynamic)>(object));
+  Expect.isTrue(isBase<(dynamic, String)>(object));
+  Expect.isTrue(isBase<(int, String)>(object));
+
+  Expect.isFalse(isBase<(String, dynamic)>(object));
+  Expect.isFalse(isBase<(dynamic, int)>(object));
+}
+
+bool isBase<T>(dynamic o) => o is Base<T>;
+
+class Base<T> {}
+
+class Sub<A, B> implements Base<(A, B)> {}