Deprecate smart cast on alien derived property #KT-48101 Fixed

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java

@@ -28094,6 +28094,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                     runTest("compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance.kt");
                 }
 
+                @Test
+                @TestMetadata("otherModuleInheritance_after.kt")
+                public void testOtherModuleInheritance_after() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance_after.kt");
+                }
+
                 @Test
                 @TestMetadata("protected.kt")
                 public void testProtected() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java

@@ -28094,6 +28094,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                     runTest("compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance.kt");
                 }
 
+                @Test
+                @TestMetadata("otherModuleInheritance_after.kt")
+                public void testOtherModuleInheritance_after() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance_after.kt");
+                }
+
                 @Test
                 @TestMetadata("protected.kt")
                 public void testProtected() throws Exception {

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

@@ -41,25 +41,37 @@ class DataFlowValue(
         // or protected / public member value from the same module without open / custom getter
         // Smart casts are completely safe
         STABLE_VALUE("stable val"),
+
         // Block, or if / else, or when
         STABLE_COMPLEX_EXPRESSION("complex expression", ""),
+
         // Should be unstable, but can be used as stable with deprecation warning
         LEGACY_STABLE_LOCAL_DELEGATED_PROPERTY("local delegated property"),
+
         // Member value with open / custom getter
         // Smart casts are not safe
         PROPERTY_WITH_GETTER("custom getter", "property that has open or custom getter"),
+
+        // Protected / public member value from derived class from another module
+        // 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 another module
         // Smart casts are not safe
         ALIEN_PUBLIC_PROPERTY("alien public", "public API property declared in different module"),
+
         // Local variable not yet captured by a changing closure
         // Smart casts are safe but possible changes in loops / closures ahead must be taken into account
         STABLE_VARIABLE("stable var", "local variable that can be changed since the check in a loop"),
+
         // Local variable already captured by a changing closure
         // Smart casts are not safe
         CAPTURED_VARIABLE("captured var", "local variable that is captured by a changing closure"),
+
         // Member variable regardless of its visibility
         // Smart casts are not safe
         MUTABLE_PROPERTY("member", "mutable property that could have been changed by this time"),
+
         // Some complex expression
         // Smart casts are not safe
         OTHER("other", "complex expression");
@@ -74,7 +86,8 @@ class DataFlowValue(
     val isStable = kind == Kind.STABLE_VALUE ||
             kind == Kind.STABLE_VARIABLE ||
             kind == Kind.STABLE_COMPLEX_EXPRESSION ||
-            kind == Kind.LEGACY_STABLE_LOCAL_DELEGATED_PROPERTY
+            kind == Kind.LEGACY_STABLE_LOCAL_DELEGATED_PROPERTY ||
+            kind == Kind.LEGACY_ALIEN_BASE_PROPERTY
 
     val canBeBound get() = identifierInfo.canBeBound
 

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

@@ -19,7 +19,10 @@ import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.types.expressions.AssignedVariablesSearcher
 import org.jetbrains.kotlin.types.expressions.PreliminaryDeclarationVisitor
 
-internal fun PropertyDescriptor.propertyKind(usageModule: ModuleDescriptor?): DataFlowValue.Kind {
+internal fun PropertyDescriptor.propertyKind(
+    usageModule: ModuleDescriptor?,
+    languageVersionSettings: LanguageVersionSettings
+): DataFlowValue.Kind {
     if (isVar) return DataFlowValue.Kind.MUTABLE_PROPERTY
     if (isOverridable) return DataFlowValue.Kind.PROPERTY_WITH_GETTER
     if (!hasDefaultGetter()) return DataFlowValue.Kind.PROPERTY_WITH_GETTER
@@ -28,11 +31,30 @@ internal fun PropertyDescriptor.propertyKind(usageModule: ModuleDescriptor?): Da
         if (!areCompiledTogether(usageModule, declarationModule)) {
             return DataFlowValue.Kind.ALIEN_PUBLIC_PROPERTY
         }
+        if (kind == CallableMemberDescriptor.Kind.FAKE_OVERRIDE) {
+            if (overriddenDescriptors.any { isDeclaredInAnotherModule(usageModule) }) {
+                return if (!languageVersionSettings.supportsFeature(LanguageFeature.ProhibitSmartcastsOnPropertyFromAlienBaseClass)) {
+                    DataFlowValue.Kind.LEGACY_ALIEN_BASE_PROPERTY
+                } else {
+                    DataFlowValue.Kind.ALIEN_PUBLIC_PROPERTY
+                }
+            }
+        }
     }
     return DataFlowValue.Kind.STABLE_VALUE
 }
 
-internal fun areCompiledTogether(
+private fun PropertyDescriptor.isDeclaredInAnotherModule(usageModule: ModuleDescriptor?): Boolean {
+    if (!areCompiledTogether(usageModule, DescriptorUtils.getContainingModule(this))) {
+        return true
+    }
+    if (kind == CallableMemberDescriptor.Kind.FAKE_OVERRIDE) {
+        return overriddenDescriptors.any { it.isDeclaredInAnotherModule(usageModule) }
+    }
+    return false
+}
+
+private fun areCompiledTogether(
     usageModule: ModuleDescriptor?,
     declarationModule: ModuleDescriptor,
 ): Boolean {
@@ -49,7 +71,7 @@ internal fun VariableDescriptor.variableKind(
     languageVersionSettings: LanguageVersionSettings
 ): DataFlowValue.Kind {
     if (this is PropertyDescriptor) {
-        return propertyKind(usageModule)
+        return propertyKind(usageModule, languageVersionSettings)
     }
 
     if (this is LocalVariableDescriptor && this.isDelegated) {

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

@@ -226,7 +226,9 @@ class SmartCastManager(private val argumentTypeResolver: ArgumentTypeResolver) {
         ) {
             if (KotlinBuiltIns.isNullableNothing(type)) return
             if (dataFlowValue.isStable) {
-                if (dataFlowValue.kind == DataFlowValue.Kind.LEGACY_STABLE_LOCAL_DELEGATED_PROPERTY) {
+                if (dataFlowValue.kind == DataFlowValue.Kind.LEGACY_ALIEN_BASE_PROPERTY ||
+                    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/publicVals/otherModuleInheritance.fir.kt

@@ -1,3 +1,4 @@
+// !LANGUAGE: -ProhibitSmartcastsOnPropertyFromAlienBaseClass
 // MODULE: m1
 // FILE: A.kt
 

compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance.kt

@@ -1,3 +1,4 @@
+// !LANGUAGE: -ProhibitSmartcastsOnPropertyFromAlienBaseClass
 // MODULE: m1
 // FILE: A.kt
 
@@ -10,7 +11,7 @@ open class Generic<T>(val y: T)
 class Derived : Base("123") {
     fun foo() {
         if (x is String) {
-            <!DEBUG_INFO_SMARTCAST!>x<!>.length // impossible since `x` is in another module. FE1.0 allows this due to KT-47225
+            <!DEBUG_INFO_SMARTCAST, DEPRECATED_SMARTCAST!>x<!>.length // impossible since `x` is in another module. FE1.0 allows this due to KT-47225
         }
     }
 }
@@ -19,7 +20,7 @@ class MyGeneric : Generic<Number>(42) {
     private fun baz(arg: Int) {}
     fun bar() {
         if (y is Int) {
-            baz(<!DEBUG_INFO_SMARTCAST!>y<!>) // impossible since `y` is in another module. FE1.0 allows this due to KT-47225
+            baz(<!DEBUG_INFO_SMARTCAST, DEPRECATED_SMARTCAST!>y<!>) // impossible since `y` is in another module. FE1.0 allows this due to KT-47225
         }
     }
 }

compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance_after.kt

@@ -0,0 +1,27 @@
+// FIR_IDENTICAL
+// !LANGUAGE: +ProhibitSmartcastsOnPropertyFromAlienBaseClass
+// MODULE: m1
+// FILE: A.kt
+
+open class Base(val x: Any)
+open class Generic<T>(val y: T)
+
+// MODULE: m2(m1)
+// FILE: B.kt
+
+class Derived : Base("123") {
+    fun foo() {
+        if (x is String) {
+            <!SMARTCAST_IMPOSSIBLE!>x<!>.length // impossible since `x` is in another module. FE1.0 allows this due to KT-47225
+        }
+    }
+}
+
+class MyGeneric : Generic<Number>(42) {
+    private fun baz(arg: Int) {}
+    fun bar() {
+        if (y is Int) {
+            baz(<!SMARTCAST_IMPOSSIBLE!>y<!>) // impossible since `y` is in another module. FE1.0 allows this due to KT-47225
+        }
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance_after.txt

@@ -0,0 +1,40 @@
+// -- Module: <m1> --
+package
+
+public open class Base {
+    public constructor Base(/*0*/ x: kotlin.Any)
+    public final val x: kotlin.Any
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public open class Generic</*0*/ T> {
+    public constructor Generic</*0*/ T>(/*0*/ y: T)
+    public final val y: T
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+// -- Module: <m2> --
+package
+
+public final class Derived : Base {
+    public constructor Derived()
+    public final override /*1*/ /*fake_override*/ val x: kotlin.Any
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class MyGeneric : Generic<kotlin.Number> {
+    public constructor MyGeneric()
+    public final override /*1*/ /*fake_override*/ val y: kotlin.Number
+    public final fun bar(): kotlin.Unit
+    private final fun baz(/*0*/ arg: kotlin.Int): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java

@@ -28184,6 +28184,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     runTest("compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance.kt");
                 }
 
+                @Test
+                @TestMetadata("otherModuleInheritance_after.kt")
+                public void testOtherModuleInheritance_after() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance_after.kt");
+                }
+
                 @Test
                 @TestMetadata("protected.kt")
                 public void testProtected() throws Exception {

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

@@ -227,6 +227,7 @@ enum class LanguageFeature(
     OptInRelease(KOTLIN_1_7),
     ProhibitNonExhaustiveWhenOnAlgebraicTypes(KOTLIN_1_7, kind = BUG_FIX),
     UseBuilderInferenceWithoutAnnotation(KOTLIN_1_7),
+    ProhibitSmartcastsOnPropertyFromAlienBaseClass(KOTLIN_1_7, kind = BUG_FIX),
 
     // Temporarily disabled, see KT-27084/KT-22379
     SoundSmartcastFromLoopConditionForLoopAssignedVariables(sinceVersion = null, kind = BUG_FIX),

idea/idea-frontend-fir/idea-fir-low-level-api/tests/org/jetbrains/kotlin/idea/fir/low/level/api/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java

@@ -28094,6 +28094,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                     runTest("compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance.kt");
                 }
 
+                @Test
+                @TestMetadata("otherModuleInheritance_after.kt")
+                public void testOtherModuleInheritance_after() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/smartCasts/publicVals/otherModuleInheritance_after.kt");
+                }
+
                 @Test
                 @TestMetadata("protected.kt")
                 public void testProtected() throws Exception {