K1: introduce smartcast deprecation for a public API property in invisible class

#KT-56511 Fixed
Related to KT-57290

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DataFlowValue.kt

@@ -57,6 +57,13 @@ class DataFlowValue(
         // Should be unstable, but can be used as stable with deprecation warning
         LEGACY_ALIEN_BASE_PROPERTY("alien derived", "property declared in base class from different module"),
 
+        // Protected / public member value from derived class from another module, in case the derived class is non-public API
+        // Should be unstable, but can be used as stable with deprecation warning
+        LEGACY_ALIEN_BASE_PROPERTY_INHERITED_IN_INVISIBLE_CLASS(
+            "alien inherited in invisible",
+            "property declared in base class from different module inherited in non-public API class"
+        ),
+
         // Protected / public member value from another module
         // Smart casts are not safe
         ALIEN_PUBLIC_PROPERTY("alien public", "public API property declared in different module"),
@@ -88,7 +95,8 @@ class DataFlowValue(
             kind == Kind.STABLE_VARIABLE ||
             kind == Kind.STABLE_COMPLEX_EXPRESSION ||
             kind == Kind.LEGACY_STABLE_LOCAL_DELEGATED_PROPERTY ||
-            kind == Kind.LEGACY_ALIEN_BASE_PROPERTY
+            kind == Kind.LEGACY_ALIEN_BASE_PROPERTY ||
+            kind == Kind.LEGACY_ALIEN_BASE_PROPERTY_INHERITED_IN_INVISIBLE_CLASS
 
     val canBeBound get() = identifierInfo.canBeBound
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DataFlowValueKindUtils.kt

@@ -7,7 +7,7 @@ package org.jetbrains.kotlin.resolve.calls.smartcasts
 
 import org.jetbrains.kotlin.cfg.getDeclarationDescriptorIncludingConstructors
 import org.jetbrains.kotlin.cfg.getElementParentDeclaration
-import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.config.LanguageFeature.*
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.impl.LocalVariableDescriptor
@@ -26,21 +26,29 @@ internal fun PropertyDescriptor.propertyKind(
     if (isVar) return DataFlowValue.Kind.MUTABLE_PROPERTY
     if (isOverridable) return DataFlowValue.Kind.PROPERTY_WITH_GETTER
     if (!hasDefaultGetter()) return DataFlowValue.Kind.PROPERTY_WITH_GETTER
-    if (!isInvisibleFromOtherModules()) {
+    val originalDescriptor = DescriptorUtils.unwrapFakeOverride(this)
-        val declarationModule = DescriptorUtils.getContainingModule(this)
+    val isInvisibleFromOtherModuleUnwrappedFakeOverride = originalDescriptor.isInvisibleFromOtherModules()
-        if (!areCompiledTogether(usageModule, declarationModule)) {
+    if (isInvisibleFromOtherModuleUnwrappedFakeOverride) return DataFlowValue.Kind.STABLE_VALUE
-            return DataFlowValue.Kind.ALIEN_PUBLIC_PROPERTY
+
-        }
+    if (kind == CallableMemberDescriptor.Kind.FAKE_OVERRIDE) {
-        if (kind == CallableMemberDescriptor.Kind.FAKE_OVERRIDE) {
+        if (overriddenDescriptors.any { isDeclaredInAnotherModule(usageModule) }) {
-            if (overriddenDescriptors.any { isDeclaredInAnotherModule(usageModule) }) {
+            val deprecationForInvisibleFakeOverride =
-                return if (!languageVersionSettings.supportsFeature(LanguageFeature.ProhibitSmartcastsOnPropertyFromAlienBaseClass)) {
+                isInvisibleFromOtherModules() != isInvisibleFromOtherModuleUnwrappedFakeOverride &&
+                        !languageVersionSettings.supportsFeature(ProhibitSmartcastsOnPropertyFromAlienBaseClassInheritedInInvisibleClass)
+            return when {
+                deprecationForInvisibleFakeOverride ->
+                    DataFlowValue.Kind.LEGACY_ALIEN_BASE_PROPERTY_INHERITED_IN_INVISIBLE_CLASS
+                !languageVersionSettings.supportsFeature(ProhibitSmartcastsOnPropertyFromAlienBaseClass) ->
                     DataFlowValue.Kind.LEGACY_ALIEN_BASE_PROPERTY
-                } else {
+                else ->
                     DataFlowValue.Kind.ALIEN_PUBLIC_PROPERTY
-                }
             }
         }
     }
+
+    val declarationModule = DescriptorUtils.getContainingModule(originalDescriptor)
+    if (!areCompiledTogether(usageModule, declarationModule)) return DataFlowValue.Kind.ALIEN_PUBLIC_PROPERTY
+
     return DataFlowValue.Kind.STABLE_VALUE
 }
 
@@ -76,7 +84,7 @@ internal fun VariableDescriptor.variableKind(
 
     if (this is LocalVariableDescriptor && this.isDelegated) {
         // Local delegated property: normally unstable, but can be treated as stable in legacy mode
-        return if (languageVersionSettings.supportsFeature(LanguageFeature.ProhibitSmartcastsOnLocalDelegatedProperty))
+        return if (languageVersionSettings.supportsFeature(ProhibitSmartcastsOnLocalDelegatedProperty))
             DataFlowValue.Kind.PROPERTY_WITH_GETTER
         else
             DataFlowValue.Kind.LEGACY_STABLE_LOCAL_DELEGATED_PROPERTY
@@ -101,7 +109,7 @@ internal fun VariableDescriptor.variableKind(
     val variableContainingDeclaration = this.containingDeclaration
     if (isAccessedInsideClosure(variableContainingDeclaration, bindingContext, accessElement)) {
         // stable iff we have no writers in closures AND this closure is AFTER all writers
-        return if (preliminaryVisitor.languageVersionSettings.supportsFeature(LanguageFeature.CapturedInClosureSmartCasts) &&
+        return if (preliminaryVisitor.languageVersionSettings.supportsFeature(CapturedInClosureSmartCasts) &&
             hasNoWritersInClosures(variableContainingDeclaration, writers, bindingContext) &&
             isAccessedInsideClosureAfterAllWriters(writers, accessElement)
         ) {
@@ -157,7 +165,6 @@ private fun isAccessedBeforeAllClosureWriters(
     return true
 }
 
-
 private fun DeclarationDescriptorWithVisibility.isInvisibleFromOtherModules(): Boolean {
     if (DescriptorVisibilities.INVISIBLE_FROM_OTHER_MODULES.contains(visibility)) return true
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/SmartCastManager.kt

@@ -226,6 +226,7 @@ class SmartCastManager(private val argumentTypeResolver: ArgumentTypeResolver) {
             if (KotlinBuiltIns.isNullableNothing(type)) return
             if (dataFlowValue.isStable) {
                 if (dataFlowValue.kind == DataFlowValue.Kind.LEGACY_ALIEN_BASE_PROPERTY ||
+                    dataFlowValue.kind == DataFlowValue.Kind.LEGACY_ALIEN_BASE_PROPERTY_INHERITED_IN_INVISIBLE_CLASS ||
                     dataFlowValue.kind == DataFlowValue.Kind.LEGACY_STABLE_LOCAL_DELEGATED_PROPERTY
                 ) {
                     trace.report(Errors.DEPRECATED_SMARTCAST.on(expression, type, expression.text, dataFlowValue.kind.description))

compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.diag.txt

@@ -0,0 +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
+            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
+        i.x.length
+        ^
+

compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.fir.kt

@@ -1,3 +1,4 @@
+// RENDER_DIAGNOSTICS_FULL_TEXT
 // MODULE: m1
 // FILE: A.kt
 
@@ -13,3 +14,11 @@ private class Derived : Base("123") {
         }
     }
 }
+
+internal class Internal : Base("456")
+
+internal fun bar(i: Internal) {
+    if (i.x is String) {
+        i.x.length
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/smartCastOnAlienPropertyFromInnerClass.kt

@@ -1,3 +1,4 @@
+// RENDER_DIAGNOSTICS_FULL_TEXT
 // MODULE: m1
 // FILE: A.kt
 
@@ -9,7 +10,15 @@ open class Base(val x: Any)
 private class Derived : Base("123") {
     fun foo() {
         if (x is String) {
-            <!DEBUG_INFO_SMARTCAST!>x<!>.length
+            <!DEBUG_INFO_SMARTCAST, DEPRECATED_SMARTCAST!>x<!>.length
         }
     }
 }
+
+internal class Internal : Base("456")
+
+internal fun bar(i: Internal) {
+    if (i.x is String) {
+        <!DEBUG_INFO_SMARTCAST, DEPRECATED_SMARTCAST!>i.x<!>.length
+    }
+}

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -285,6 +285,7 @@ enum class LanguageFeature(
 
     EnhanceNullabilityOfPrimitiveArrays(KOTLIN_2_0, kind = BUG_FIX), // KT-54521
     AllowEmptyIntersectionsInResultTypeResolver(KOTLIN_2_0, kind = OTHER), // KT-51221
+    ProhibitSmartcastsOnPropertyFromAlienBaseClassInheritedInInvisibleClass(KOTLIN_2_0, kind = BUG_FIX), // KT-57290
 
     // End of 2.* language features --------------------------------------------------