diff --git a/python/python-psi-impl/src/com/jetbrains/python/psi/PyKnownDecoratorUtil.java b/python/python-psi-impl/src/com/jetbrains/python/psi/PyKnownDecoratorUtil.java
index 78e6e849c9b2..ffb9441df799 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/psi/PyKnownDecoratorUtil.java
+++ b/python/python-psi-impl/src/com/jetbrains/python/psi/PyKnownDecoratorUtil.java
@@ -145,11 +145,6 @@ public final class PyKnownDecoratorUtil {
     return !allDecoratorsAreKnown(decoratable, decorators) || decorators.contains(UNITTEST_MOCK_PATCH);
   }
 
-  public static boolean hasChangingReturnTypeDecorator(@NotNull PyDecoratable decoratable, @NotNull TypeEvalContext context) {
-    final List<PyKnownDecorator> decorators = getKnownDecorators(decoratable, context);
-    return ContainerUtil.exists(decorators, d -> d == UNITTEST_MOCK_PATCH);
-  }
-
   public static boolean hasUnknownOrUpdatingAttributesDecorator(@NotNull PyDecoratable decoratable, @NotNull TypeEvalContext context) {
     final List<PyKnownDecorator> decorators = getKnownDecorators(decoratable, context);
 
diff --git a/python/python-psi-impl/src/com/jetbrains/python/psi/types/PyTypeChecker.java b/python/python-psi-impl/src/com/jetbrains/python/psi/types/PyTypeChecker.java
index b2f1654b5ed4..099fed1d1402 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/psi/types/PyTypeChecker.java
+++ b/python/python-psi-impl/src/com/jetbrains/python/psi/types/PyTypeChecker.java
@@ -1103,13 +1103,6 @@ public final class PyTypeChecker {
     if (type == null || (genericsAreUnknown && type instanceof PyTypeParameterType)) {
       return true;
     }
-    if (type instanceof PyFunctionType) {
-      final PyCallable callable = ((PyFunctionType)type).getCallable();
-      if (callable instanceof PyDecoratable &&
-          PyKnownDecoratorUtil.hasChangingReturnTypeDecorator((PyDecoratable)callable, context)) {
-        return true;
-      }
-    }
     if (type instanceof PyUnionType union) {
       if (!PyUnionType.isStrictSemanticsEnabled()) {
         return ContainerUtil.exists(union.getMembers(), member -> isUnknown(member, genericsAreUnknown, context));