diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
index 002ed2df5c6..408aa2132d7 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
@@ -30181,9 +30181,15 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
             }
 
             @Test
-            @TestMetadata("smartCastOnAlienPropertyFromInnerClass.kt")
-            public void testSmartCastOnAlienPropertyFromInnerClass() throws Exception {
-                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.kt");
+            @TestMetadata("smartCastOnAlienPropertyFromInvisibleClass.kt")
+            public void testSmartCastOnAlienPropertyFromInvisibleClass() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.kt");
+            }
+
+            @Test
+            @TestMetadata("smartCastOnAlienPropertyFromInvisibleClassForbidden.kt")
+            public void testSmartCastOnAlienPropertyFromInvisibleClassForbidden() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClassForbidden.kt");
             }
 
             @Test
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
index 361ac71ae5e..361ff86a71b 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
@@ -30181,9 +30181,15 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
             }
 
             @Test
-            @TestMetadata("smartCastOnAlienPropertyFromInnerClass.kt")
-            public void testSmartCastOnAlienPropertyFromInnerClass() throws Exception {
-                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.kt");
+            @TestMetadata("smartCastOnAlienPropertyFromInvisibleClass.kt")
+            public void testSmartCastOnAlienPropertyFromInvisibleClass() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.kt");
+            }
+
+            @Test
+            @TestMetadata("smartCastOnAlienPropertyFromInvisibleClassForbidden.kt")
+            public void testSmartCastOnAlienPropertyFromInvisibleClassForbidden() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClassForbidden.kt");
             }
 
             @Test
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
index 4248f350a59..874ee56185f 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
@@ -30277,9 +30277,15 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
             }
 
             @Test
-            @TestMetadata("smartCastOnAlienPropertyFromInnerClass.kt")
-            public void testSmartCastOnAlienPropertyFromInnerClass() throws Exception {
-                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.kt");
+            @TestMetadata("smartCastOnAlienPropertyFromInvisibleClass.kt")
+            public void testSmartCastOnAlienPropertyFromInvisibleClass() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.kt");
+            }
+
+            @Test
+            @TestMetadata("smartCastOnAlienPropertyFromInvisibleClassForbidden.kt")
+            public void testSmartCastOnAlienPropertyFromInvisibleClassForbidden() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClassForbidden.kt");
             }
 
             @Test
diff --git a/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.diag.txt b/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.diag.txt
similarity index 70%
rename from compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.diag.txt
rename to compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.diag.txt
index 5020b6e1af0..ef0a171a36d 100644
--- a/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.diag.txt
+++ b/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.diag.txt
@@ -1,10 +1,10 @@
 // -- Module: <m1> --
 
 // -- Module: <m2> --
-/B.kt:13:13: warning: smart cast to 'String' is deprecated, because 'x' is a property declared in base class from different module inherited in non-public API class
+/B.kt:14:13: warning: smart cast to 'String' is deprecated, because 'x' is a property declared in base class from different module inherited in non-public API class
             x.length
             ^
-/B.kt:22:9: warning: smart cast to 'String' is deprecated, because 'i.x' is a property declared in base class from different module inherited in non-public API class
+/B.kt:23:9: warning: smart cast to 'String' is deprecated, because 'i.x' is a property declared in base class from different module inherited in non-public API class
         i.x.length
         ^
 
diff --git a/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.fir.kt b/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.fir.kt
similarity index 73%
rename from compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.fir.kt
rename to compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.fir.kt
index d78f2d16c82..8f30438a1f4 100644
--- a/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.fir.kt
+++ b/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.fir.kt
@@ -1,3 +1,4 @@
+// !LANGUAGE: -ProhibitSmartcastsOnPropertyFromAlienBaseClassInheritedInInvisibleClass
 // RENDER_DIAGNOSTICS_FULL_TEXT
 // MODULE: m1
 // FILE: A.kt
@@ -19,6 +20,6 @@ internal class Internal : Base("456")
 
 internal fun bar(i: Internal) {
     if (i.x is String) {
-        i.x.length
+        <!SMARTCAST_IMPOSSIBLE!>i.x<!>.length
     }
 }
diff --git a/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.kt b/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.kt
similarity index 84%
rename from compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.kt
rename to compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.kt
index d8694c2e9ce..4a2c814cdc4 100644
--- a/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.kt
+++ b/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.kt
@@ -1,3 +1,4 @@
+// !LANGUAGE: -ProhibitSmartcastsOnPropertyFromAlienBaseClassInheritedInInvisibleClass
 // RENDER_DIAGNOSTICS_FULL_TEXT
 // MODULE: m1
 // FILE: A.kt
diff --git a/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClassForbidden.kt b/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClassForbidden.kt
new file mode 100644
index 00000000000..b79e0930ef6
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClassForbidden.kt
@@ -0,0 +1,25 @@
+// FIR_IDENTICAL
+// !LANGUAGE: +ProhibitSmartcastsOnPropertyFromAlienBaseClassInheritedInInvisibleClass
+// MODULE: m1
+// FILE: A.kt
+
+open class Base(val x: Any)
+
+// MODULE: m2(m1)
+// FILE: B.kt
+
+private class Derived : Base("123") {
+    fun foo() {
+        if (x is String) {
+            <!SMARTCAST_IMPOSSIBLE!>x<!>.length
+        }
+    }
+}
+
+internal class Internal : Base("456")
+
+internal fun bar(i: Internal) {
+    if (i.x is String) {
+        <!SMARTCAST_IMPOSSIBLE!>i.x<!>.length
+    }
+}
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
index ccd1cd0e892..02c40eda1a6 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
@@ -30277,9 +30277,15 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
             }
 
             @Test
-            @TestMetadata("smartCastOnAlienPropertyFromInnerClass.kt")
-            public void testSmartCastOnAlienPropertyFromInnerClass() throws Exception {
-                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.kt");
+            @TestMetadata("smartCastOnAlienPropertyFromInvisibleClass.kt")
+            public void testSmartCastOnAlienPropertyFromInvisibleClass() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClass.kt");
+            }
+
+            @Test
+            @TestMetadata("smartCastOnAlienPropertyFromInvisibleClassForbidden.kt")
+            public void testSmartCastOnAlienPropertyFromInvisibleClassForbidden() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInvisibleClassForbidden.kt");
             }
 
             @Test