[dart2js] add regression test for issue 48571

Global type inference incorrectly handles conditions nested within
subexpressions and accidentally carries information from those
in the context of outer conditions.

Change-Id: I99e0af3da65590acb9429771b318b7da8f3b7f14
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/240320
Reviewed-by: Stephen Adams <sra@google.com>

pkg/compiler/test/inference/data/issue_48571.dart

@@ -0,0 +1,83 @@
+// 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.
+
+/*member: Base.:[subclass=Base]*/
+abstract class Base {}
+
+/*member: Child1.:[exact=Child1]*/
+class Child1 extends Base {}
+
+/*member: Child2.:[exact=Child2]*/
+class Child2 extends Base {}
+
+/*member: trivial:Value([exact=JSBool], value: true)*/
+bool trivial(/*[exact=JSBool]*/ x) => true;
+
+/*member: either:Union([exact=Child1], [exact=Child2])*/
+Base either = DateTime.now()
+            . /*[exact=DateTime]*/ millisecondsSinceEpoch /*invoke: [subclass=JSInt]*/ >
+        0
+    ? Child2()
+    : Child1();
+
+/*member: test1:[null|exact=Child1]*/
+test1() {
+  Base child = either;
+  if (trivial(child is Child1 && true)) return child;
+  return null;
+}
+
+/*member: test2:[null|exact=Child1]*/
+test2() {
+  Base child = either;
+  if (child is Child1 || trivial(child is Child1 && true)) return child;
+  return null;
+}
+
+/*member: test3:[null]*/
+test3() {
+  Base child = either;
+  if (trivial(child is Child1 && true) && child is Child2) return child;
+  return null;
+}
+
+/*member: test4:[null]*/
+test4() {
+  Base child = either;
+  if (child is Child2 && trivial(child is Child1 && true)) return child;
+  return null;
+}
+
+/*member: test5:[null|exact=Child1]*/
+test5() {
+  Base child = either;
+  if ((child is Child1 && true) /*invoke: [exact=JSBool]*/ == false)
+    return child;
+  return null;
+}
+
+/*member: test6:Union(null, [exact=Child1], [exact=Child2])*/
+test6() {
+  Base child = either;
+  if (trivial(child is Child1 ? false : true)) return child;
+  return null;
+}
+
+/*member: test7:[null|exact=Child1]*/
+test7() {
+  Base child = either;
+  if (trivial(trivial(child is Child1 && true))) return child;
+  return null;
+}
+
+/*member: main:[null]*/
+main() {
+  test1();
+  test2();
+  test3();
+  test4();
+  test5();
+  test6();
+  test7();
+}

tests/web/regress/issue/48571_test.dart

@@ -0,0 +1,66 @@
+// 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:expect/expect.dart';
+
+abstract class Base {}
+
+class Child1 extends Base {}
+
+class Child2 extends Base {}
+
+bool trivial(x) => true;
+Base either = DateTime.now().millisecondsSinceEpoch > 0 ? Child2() : Child1();
+
+test1() {
+  Base child = either;
+  if (trivial(child is Child1 && true)) return child;
+  return null;
+}
+
+test2() {
+  Base child = either;
+  if (child is Child1 || trivial(child is Child1 && true)) return child;
+  return null;
+}
+
+test3() {
+  Base child = either;
+  if (trivial(child is Child1 && true) && child is Child2) return child;
+  return null;
+}
+
+test4() {
+  Base child = either;
+  if (child is Child2 && trivial(child is Child1 && true)) return child;
+  return null;
+}
+
+test5() {
+  Base child = either;
+  if ((child is Child1 && true) == false) return child;
+  return null;
+}
+
+test6() {
+  Base child = either;
+  if (trivial(child is Child1 ? false : true)) return child;
+  return null;
+}
+
+test7() {
+  Base child = either;
+  if (trivial(trivial(child is Child1 && true))) return child;
+  return null;
+}
+
+main() {
+  Expect.isTrue(test1() is Child2, "test1");
+  Expect.isTrue(test2() is Child2, "test2");
+  Expect.isTrue(test3() is Child2, "test3");
+  Expect.isTrue(test4() is Child2, "test4");
+  Expect.isTrue(test5() is Child2, "test5");
+  Expect.isTrue(test6() is Child2, "test6");
+  Expect.isTrue(test7() is Child2, "test7");
+}

tests/web_2/regress/issue/48571_test.dart

@@ -0,0 +1,68 @@
+// 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.
+
+// @dart = 2.7
+
+import 'package:expect/expect.dart';
+
+abstract class Base {}
+
+class Child1 extends Base {}
+
+class Child2 extends Base {}
+
+bool trivial(x) => true;
+Base either = DateTime.now().millisecondsSinceEpoch > 0 ? Child2() : Child1();
+
+test1() {
+  Base child = either;
+  if (trivial(child is Child1 && true)) return child;
+  return null;
+}
+
+test2() {
+  Base child = either;
+  if (child is Child1 || trivial(child is Child1 && true)) return child;
+  return null;
+}
+
+test3() {
+  Base child = either;
+  if (trivial(child is Child1 && true) && child is Child2) return child;
+  return null;
+}
+
+test4() {
+  Base child = either;
+  if (child is Child2 && trivial(child is Child1 && true)) return child;
+  return null;
+}
+
+test5() {
+  Base child = either;
+  if ((child is Child1 && true) == false) return child;
+  return null;
+}
+
+test6() {
+  Base child = either;
+  if (trivial(child is Child1 ? false : true)) return child;
+  return null;
+}
+
+test7() {
+  Base child = either;
+  if (trivial(trivial(child is Child1 && true))) return child;
+  return null;
+}
+
+main() {
+  Expect.isTrue(test1() is Child2, "test1");
+  Expect.isTrue(test2() is Child2, "test2");
+  Expect.isTrue(test3() is Child2, "test3");
+  Expect.isTrue(test4() is Child2, "test4");
+  Expect.isTrue(test5() is Child2, "test5");
+  Expect.isTrue(test6() is Child2, "test6");
+  Expect.isTrue(test7() is Child2, "test7");
+}