diff --git a/pkg/compiler/lib/src/js_backend/specialized_checks.dart b/pkg/compiler/lib/src/js_backend/specialized_checks.dart
index c16d94e87d2..ed26a6cdf12 100644
--- a/pkg/compiler/lib/src/js_backend/specialized_checks.dart
+++ b/pkg/compiler/lib/src/js_backend/specialized_checks.dart
@@ -30,20 +30,24 @@ class InstanceOfIsTestSpecialization implements IsTestSpecialization {
 
 class SpecializedChecks {
   static IsTestSpecialization? findIsTestSpecialization(
-      DartType dartType, MemberEntity compiland, JClosedWorld closedWorld) {
+      DartType dartType, MemberEntity compiland, JClosedWorld closedWorld,
+      {required bool experimentNullSafetyChecks}) {
     if (dartType is LegacyType) {
       DartType base = dartType.baseType;
       // `Never*` accepts only `null`.
       if (base is NeverType) return SimpleIsTestSpecialization.isNull;
       // `Object*` is top and should be handled by constant folding.
       if (base.isObject) return null;
-      return _findIsTestSpecialization(base, compiland, closedWorld);
+      return _findIsTestSpecialization(base, compiland, closedWorld,
+          experimentNullSafetyChecks: experimentNullSafetyChecks);
     }
-    return _findIsTestSpecialization(dartType, compiland, closedWorld);
+    return _findIsTestSpecialization(dartType, compiland, closedWorld,
+        experimentNullSafetyChecks: experimentNullSafetyChecks);
   }
 
   static IsTestSpecialization? _findIsTestSpecialization(
-      DartType dartType, MemberEntity compiland, JClosedWorld closedWorld) {
+      DartType dartType, MemberEntity compiland, JClosedWorld closedWorld,
+      {required bool experimentNullSafetyChecks}) {
     if (dartType is InterfaceType) {
       ClassEntity element = dartType.element;
       JCommonElements commonElements = closedWorld.commonElements;
@@ -98,6 +102,10 @@ class SpecializedChecks {
         return SimpleIsTestSpecialization.isNotNull;
       }
 
+      if (experimentNullSafetyChecks && dartType.typeArguments.isNotEmpty) {
+        return null;
+      }
+
       ClassHierarchy classHierarchy = closedWorld.classHierarchy;
       InterceptorData interceptorData = closedWorld.interceptorData;
       OutputUnitData outputUnitData = closedWorld.outputUnitData;
diff --git a/pkg/compiler/lib/src/ssa/optimize.dart b/pkg/compiler/lib/src/ssa/optimize.dart
index 4043f1b6be8..12c34d020d0 100644
--- a/pkg/compiler/lib/src/ssa/optimize.dart
+++ b/pkg/compiler/lib/src/ssa/optimize.dart
@@ -2305,7 +2305,8 @@ class SsaInstructionSimplifier extends HBaseVisitor<HInstruction>
     }
 
     final specialization = SpecializedChecks.findIsTestSpecialization(
-        node.dartType, _graph.element, _closedWorld);
+        node.dartType, _graph.element, _closedWorld,
+        experimentNullSafetyChecks: _options.experimentNullSafetyChecks);
 
     if (specialization == SimpleIsTestSpecialization.isNull ||
         specialization == SimpleIsTestSpecialization.isNotNull) {