#1244 CHECK_TOP_MERGE replaced by CheckTopMerge
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t001.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t001.dart
index 79ea14c..a92e39d 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t001.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t001.dart
@@ -22,8 +22,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<Object> {}
-class C extends CHECK_TOP_MERGE<Object> {}
+class B extends CheckTopMerge<Object> {}
+class C extends CheckTopMerge<Object> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t002.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t002.dart
index 317e44f..132918d 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t002.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t002.dart
@@ -18,8 +18,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<Object?> {}
-class C extends CHECK_TOP_MERGE<Object?> {}
+class B extends CheckTopMerge<Object?> {}
+class C extends CheckTopMerge<Object?> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t010.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t010.dart
index 05eb4c2..57e8b93 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t010.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t010.dart
@@ -19,8 +19,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<Object?> {}
-class C extends CHECK_TOP_MERGE<dynamic> {}
+class B extends CheckTopMerge<Object?> {}
+class C extends CheckTopMerge<dynamic> {}
 
 class D1 extends B implements C {}
 class D2 extends C implements B {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t011.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t011.dart
index b21d358..ed11de1 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t011.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t011.dart
@@ -19,8 +19,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<Object?> {}
-class C extends CHECK_TOP_MERGE<void   > {}
+class B extends CheckTopMerge<Object?> {}
+class C extends CheckTopMerge<void   > {}
 
 class D1 extends B implements C {}
 class D2 extends C implements B {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t015.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t015.dart
index a0de758..0cab544 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t015.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t015.dart
@@ -19,8 +19,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<int> {}
-class C extends CHECK_TOP_MERGE<int> {}
+class B extends CheckTopMerge<int> {}
+class C extends CheckTopMerge<int> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t017.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t017.dart
index 0eff235..108ab4e 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t017.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t017.dart
@@ -18,8 +18,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<int?> {}
-class C extends CHECK_TOP_MERGE<int?> {}
+class B extends CheckTopMerge<int?> {}
+class C extends CheckTopMerge<int?> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t036.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t036.dart
index 435b633..a9dc62f 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t036.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t036.dart
@@ -18,8 +18,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<Function?> {}
-class C extends CHECK_TOP_MERGE<Function?> {}
+class B extends CheckTopMerge<Function?> {}
+class C extends CheckTopMerge<Function?> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t037.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t037.dart
index accf334..c187d79 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t037.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t037.dart
@@ -18,8 +18,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<Function> {}
-class C extends CHECK_TOP_MERGE<Function> {}
+class B extends CheckTopMerge<Function> {}
+class C extends CheckTopMerge<Function> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t039.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t039.dart
index 445cd30..b3ad5f4 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t039.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t039.dart
@@ -18,8 +18,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<dynamic> {}
-class C extends CHECK_TOP_MERGE<dynamic> {}
+class B extends CheckTopMerge<dynamic> {}
+class C extends CheckTopMerge<dynamic> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t042.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t042.dart
index 5ebeebf..680196e 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t042.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t042.dart
@@ -19,8 +19,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<dynamic> {}
-class C extends CHECK_TOP_MERGE<void   > {}
+class B extends CheckTopMerge<dynamic> {}
+class C extends CheckTopMerge<void   > {}
 
 class D1 extends B implements C {}
 class D2 extends C implements B {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t048.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t048.dart
index db00d2e..7fa0efa 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t048.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t048.dart
@@ -18,8 +18,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<void> {}
-class C extends CHECK_TOP_MERGE<void> {}
+class B extends CheckTopMerge<void> {}
+class C extends CheckTopMerge<void> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t057.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t057.dart
index 35f3c65..53f4d1f 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t057.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t057.dart
@@ -18,8 +18,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<Null> {}
-class C extends CHECK_TOP_MERGE<Null> {}
+class B extends CheckTopMerge<Null> {}
+class C extends CheckTopMerge<Null> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t062.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t062.dart
index 2f226f6..33b95c3 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t062.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t062.dart
@@ -19,8 +19,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr> {}
-class C extends CHECK_TOP_MERGE<FutureOr> {}
+class B extends CheckTopMerge<FutureOr> {}
+class C extends CheckTopMerge<FutureOr> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t064.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t064.dart
index 84019dd..ec8462a 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t064.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t064.dart
@@ -20,8 +20,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr> {}
-class C extends CHECK_TOP_MERGE<Object? > {}
+class B extends CheckTopMerge<FutureOr> {}
+class C extends CheckTopMerge<Object? > {}
 
 class D1 extends C implements B {}
 class D2 extends B implements C {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t067.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t067.dart
index e8d73ab..f59d5d9 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t067.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t067.dart
@@ -20,8 +20,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr> {}
-class C extends CHECK_TOP_MERGE<dynamic > {}
+class B extends CheckTopMerge<FutureOr> {}
+class C extends CheckTopMerge<dynamic > {}
 
 class D1 extends C implements B {}
 class D2 extends B implements C {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t068.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t068.dart
index b89ded6..da506b4 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t068.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t068.dart
@@ -20,8 +20,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr> {}
-class C extends CHECK_TOP_MERGE<void    > {}
+class B extends CheckTopMerge<FutureOr> {}
+class C extends CheckTopMerge<void    > {}
 
 class D1 extends C implements B {}
 class D2 extends B implements C {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t071.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t071.dart
index 4e92073..66bbbb9 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t071.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t071.dart
@@ -21,7 +21,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr> {}
+class B extends CheckTopMerge<FutureOr> {}
 
 class D1 extends out_Object implements B {}
 class D2 extends B implements out_Object {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t072.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t072.dart
index 84d9340..2240e0d 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t072.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t072.dart
@@ -21,7 +21,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr> {}
+class B extends CheckTopMerge<FutureOr> {}
 
 class D1 extends out_void implements B {}
 class D2 extends B implements out_void {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t074.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t074.dart
index 42f70b9..03fe56e 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t074.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t074.dart
@@ -20,7 +20,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr> {}
+class B extends CheckTopMerge<FutureOr> {}
 
 class D1 extends out_FutureOr implements B {}
 class D2 extends B implements out_FutureOr {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t075.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t075.dart
index ac86507..2527902 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t075.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t075.dart
@@ -19,8 +19,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<int>> {}
-class C extends CHECK_TOP_MERGE<FutureOr<int>> {}
+class B extends CheckTopMerge<FutureOr<int>> {}
+class C extends CheckTopMerge<FutureOr<int>> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t076.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t076.dart
index 48cdd02..97e8a7a 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t076.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t076.dart
@@ -19,8 +19,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<int?>> {}
-class C extends CHECK_TOP_MERGE<FutureOr<int?>> {}
+class B extends CheckTopMerge<FutureOr<int?>> {}
+class C extends CheckTopMerge<FutureOr<int?>> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t077.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t077.dart
index 7c76054..7d6f22e 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t077.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t077.dart
@@ -19,8 +19,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<FutureOr>> {}
-class C extends CHECK_TOP_MERGE<FutureOr<FutureOr>> {}
+class B extends CheckTopMerge<FutureOr<FutureOr>> {}
+class C extends CheckTopMerge<FutureOr<FutureOr>> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t085.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t085.dart
index e5c915b..c261f1d 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t085.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t085.dart
@@ -21,7 +21,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<int?>> {}
+class B extends CheckTopMerge<FutureOr<int?>> {}
 
 class D1 extends out_FutureOr_int implements B {}
 class D2 extends B implements out_FutureOr_int {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t086.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t086.dart
index d7b26a4..dc4720c 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t086.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t086.dart
@@ -20,7 +20,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<FutureOr>> {}
+class B extends CheckTopMerge<FutureOr<FutureOr>> {}
 
 class D1 extends out_FutureOr_FutureOr implements B {}
 class D2 extends B implements out_FutureOr_FutureOr {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t089.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t089.dart
index da11746..1713372 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t089.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t089.dart
@@ -20,8 +20,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<FutureOr>> {}
-class C extends CHECK_TOP_MERGE<dynamic>  {}
+class B extends CheckTopMerge<FutureOr<FutureOr>> {}
+class C extends CheckTopMerge<dynamic>  {}
 
 class D1 extends B implements C {}
 class D2 extends C implements B {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t092.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t092.dart
index ff699f2..20882c5 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t092.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t092.dart
@@ -20,8 +20,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<FutureOr>> {}
-class C extends CHECK_TOP_MERGE<void>  {}
+class B extends CheckTopMerge<FutureOr<FutureOr>> {}
+class C extends CheckTopMerge<void>  {}
 
 class D1 extends B implements C {}
 class D2 extends C implements B {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t097.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t097.dart
index ad2c645..e66ea74 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t097.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t097.dart
@@ -18,8 +18,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<Function?> {}
-class C extends CHECK_TOP_MERGE<Function?> {}
+class B extends CheckTopMerge<Function?> {}
+class C extends CheckTopMerge<Function?> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t100.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t100.dart
index 7073072..25804d8 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t100.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t100.dart
@@ -20,7 +20,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<void> {}
+class B extends CheckTopMerge<void> {}
 
 class D1 extends out_dynamic implements B {}
 class D2 extends B implements out_dynamic {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t102.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t102.dart
index 4590992..69cea86 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t102.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t102.dart
@@ -20,8 +20,8 @@
 import "dart:async";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr> {}
-class C extends CHECK_TOP_MERGE<FutureOr<FutureOr>> {}
+class B extends CheckTopMerge<FutureOr> {}
+class C extends CheckTopMerge<FutureOr<FutureOr>> {}
 
 class D1 extends B implements C {}
 class D2 extends C implements B {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t119.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t119.dart
index 6c06221..36521b5 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t119.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t119.dart
@@ -19,8 +19,8 @@
 
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<Never> {}
-class C extends CHECK_TOP_MERGE<Never> {}
+class B extends CheckTopMerge<Never> {}
+class C extends CheckTopMerge<Never> {}
 
 class D extends B implements C {}
 
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t134.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t134.dart
index 1e759c0..5173cd0 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t134.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t134.dart
@@ -21,7 +21,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<FutureOr>> {}
+class B extends CheckTopMerge<FutureOr<FutureOr>> {}
 
 class C1 extends out_dynamic implements B {}
 class C2 extends B implements out_dynamic {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t148.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t148.dart
index f09cfbb..d442114 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t148.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t148.dart
@@ -21,7 +21,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<FutureOr>> {}
+class B extends CheckTopMerge<FutureOr<FutureOr>> {}
 
 class C1 extends out_void implements B {}
 class C2 extends B implements out_void {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t154.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t154.dart
index 69ec578..ec5c4af 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t154.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t154.dart
@@ -18,7 +18,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<Null> {}
+class B extends CheckTopMerge<Null> {}
 
 class C1 extends out_Never implements B {}
 class C2 extends B implements out_Never {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t157.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t157.dart
index ae46869..214e88f 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t157.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t157.dart
@@ -19,7 +19,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<Never> {}
+class B extends CheckTopMerge<Never> {}
 
 class C1 extends B implements out_Never {}
 //    ^^
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t158.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t158.dart
index 3c62725..375e849 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t158.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t158.dart
@@ -21,7 +21,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<dynamic> {}
+class B extends CheckTopMerge<dynamic> {}
 
 class C1 extends out_FutureOr implements B {}
 class C2 extends out_FutureOr_FutureOr implements B {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t159.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t159.dart
index 1f50704..dd9453a 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t159.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t159.dart
@@ -21,7 +21,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<Object?> {}
+class B extends CheckTopMerge<Object?> {}
 
 class C1 extends out_FutureOr implements B {}
 class C2 extends out_FutureOr_FutureOr implements B {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t160.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t160.dart
index e56d408..77bf376 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t160.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t160.dart
@@ -21,7 +21,7 @@
 import "../../../../Utils/expect.dart";
 import "override_checking_A06_opted_out_lib.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr> {}
+class B extends CheckTopMerge<FutureOr> {}
 
 class C1 extends out_FutureOr_FutureOr implements B {}
 class C2 extends B implements out_FutureOr_FutureOr {}
diff --git a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t162.dart b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t162.dart
index c198d48..9b55a80 100644
--- a/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t162.dart
+++ b/LanguageFeatures/nnbd/weak/overriding/override_checking_A06_t162.dart
@@ -20,7 +20,7 @@
 import "override_checking_A06_opted_out_lib.dart";
 import "../../../../Utils/expect.dart";
 
-class B extends CHECK_TOP_MERGE<FutureOr<FutureOr>> {}
+class B extends CheckTopMerge<FutureOr<FutureOr>> {}
 
 class C1 extends out_FutureOr implements B {}
 class C2 extends B implements out_FutureOr {}