diff --git a/tests/corelib/corelib.status b/tests/corelib/corelib.status
index d2b5d94727d..853cc32b9a5 100644
--- a/tests/corelib/corelib.status
+++ b/tests/corelib/corelib.status
@@ -42,6 +42,7 @@ bigint_test: Skip # Issue 31659
 [ $compiler == dartdevc || $compiler == dartdevk ]
 bigint_test/03: SkipSlow # modPow is very slow
 bigint_test/15: SkipSlow # modPow is very slow
+list_concurrent_modify_self_test: SkipSlow # missing check causes list to grow to whole heap
 uri_parse_test: Slow, Pass
 uri_test: Slow, Pass
 
diff --git a/tests/corelib/list_concurrent_modify_self_test.dart b/tests/corelib/list_concurrent_modify_self_test.dart
new file mode 100644
index 00000000000..cb481b7ad69
--- /dev/null
+++ b/tests/corelib/list_concurrent_modify_self_test.dart
@@ -0,0 +1,17 @@
+// Copyright (c) 2020, 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 "dart:collection";
+import "dart:typed_data";
+import "package:expect/expect.dart";
+
+void main() {
+  testConcurrentAddSelf([1, 2, 3]);
+}
+
+testConcurrentAddSelf(List list) {
+  Expect.throws(() {
+    list.addAll(list);
+  }, (e) => e is ConcurrentModificationError, "testConcurrentAddSelf($list)");
+}
diff --git a/tests/corelib/list_concurrent_modify_test.dart b/tests/corelib/list_concurrent_modify_test.dart
index 9e8d338cefe..a16352458dc 100644
--- a/tests/corelib/list_concurrent_modify_test.dart
+++ b/tests/corelib/list_concurrent_modify_test.dart
@@ -21,9 +21,6 @@ void main() {
   testConcurrentModification(new Int16List(0).toList());
   testConcurrentModification(new Uint32List(0).toList());
   testConcurrentModification(new Int32List(0).toList());
-
-  testConcurrentAddSelf([]);
-  testConcurrentAddSelf([1, 2, 3]);
 }
 
 void testConcurrentModification(List<int> list) {
@@ -77,12 +74,6 @@ void testConcurrentModification(List<int> list) {
   }
 }
 
-testConcurrentAddSelf(List list) {
-  Expect.throws(() {
-    list.addAll(list);
-  }, (e) => e is ConcurrentModificationError, "testConcurrentAddSelf($list)");
-}
-
 class MyList<E> extends ListBase<E> {
   // TODO(42496): Use a nullable list because insert() is implemented in terms
   // of length=. Change this back to `E` and remove the `as E` below when that
diff --git a/tests/corelib_2/corelib_2.status b/tests/corelib_2/corelib_2.status
index 316928feabb..5704e103781 100644
--- a/tests/corelib_2/corelib_2.status
+++ b/tests/corelib_2/corelib_2.status
@@ -53,6 +53,7 @@ bigint_test: Skip # Issue 31659
 [ $compiler == dartdevc || $compiler == dartdevk ]
 bigint_test/03: SkipSlow # modPow is very slow
 bigint_test/15: SkipSlow # modPow is very slow
+list_concurrent_modify_self_test: SkipSlow # missing check causes list to grow to whole heap
 uri_parse_test: Slow, Pass
 uri_test: Slow, Pass
 
diff --git a/tests/corelib_2/list_concurrent_modify_self_test.dart b/tests/corelib_2/list_concurrent_modify_self_test.dart
new file mode 100644
index 00000000000..cb481b7ad69
--- /dev/null
+++ b/tests/corelib_2/list_concurrent_modify_self_test.dart
@@ -0,0 +1,17 @@
+// Copyright (c) 2020, 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 "dart:collection";
+import "dart:typed_data";
+import "package:expect/expect.dart";
+
+void main() {
+  testConcurrentAddSelf([1, 2, 3]);
+}
+
+testConcurrentAddSelf(List list) {
+  Expect.throws(() {
+    list.addAll(list);
+  }, (e) => e is ConcurrentModificationError, "testConcurrentAddSelf($list)");
+}
diff --git a/tests/corelib_2/list_concurrent_modify_test.dart b/tests/corelib_2/list_concurrent_modify_test.dart
index 4d5de969602..b3fcb17f4df 100644
--- a/tests/corelib_2/list_concurrent_modify_test.dart
+++ b/tests/corelib_2/list_concurrent_modify_test.dart
@@ -23,9 +23,6 @@ void main() {
   testConcurrentModification(new Int16List(0).toList());
   testConcurrentModification(new Uint32List(0).toList());
   testConcurrentModification(new Int32List(0).toList());
-
-  testConcurrentAddSelf([]);
-  testConcurrentAddSelf([1, 2, 3]);
 }
 
 void testConcurrentModification(List<int> list) {
@@ -79,12 +76,6 @@ void testConcurrentModification(List<int> list) {
   }
 }
 
-testConcurrentAddSelf(List list) {
-  Expect.throws(() {
-    list.addAll(list);
-  }, (e) => e is ConcurrentModificationError, "testConcurrentAddSelf($list)");
-}
-
 class MyList<E> extends ListBase<E> {
   List<E> _source;
   MyList(this._source);