[FE, Java resolve] Support inheritors of sealed Java type without permits clause

This fixes a false negative NO_ELSE_IN_WHEN in K2 and incidentally
also fixes a false positive NO_ELSE_IN_WHEN in K1 since the fix is in
the common code.

#KT-62491 Fixed

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFirTestdataTestGenerated.java

@@ -45,6 +45,12 @@ public class DiagnosticCompilerTestFirTestdataTestGenerated extends AbstractDiag
             runTest("compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportAndPermits.kt");
         }
 
+        @Test
+        @TestMetadata("accessJavaFromKotlinViaStaticImportWithoutPermits.kt")
+        public void testAccessJavaFromKotlinViaStaticImportWithoutPermits() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportWithoutPermits.kt");
+        }
+
         @Test
         public void testAllFilesPresentInResolve() throws Exception {
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/fir/analysis-tests/testData/resolve"), Pattern.compile("^([^.]+)\\.kt$"), null, true);

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFirTestDataTestGenerated.java

@@ -45,6 +45,12 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFirTestDataTestGenerated
             runTest("compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportAndPermits.kt");
         }
 
+        @Test
+        @TestMetadata("accessJavaFromKotlinViaStaticImportWithoutPermits.kt")
+        public void testAccessJavaFromKotlinViaStaticImportWithoutPermits() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportWithoutPermits.kt");
+        }
+
         @Test
         public void testAllFilesPresentInResolve() throws Exception {
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/fir/analysis-tests/testData/resolve"), Pattern.compile("^([^.]+)\\.kt$"), null, true);

compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportWithoutPermits.fir.txt

@@ -0,0 +1,11 @@
+FILE: useSite.kt
+    public final fun foo(): R|kotlin/Int| {
+        ^foo Int(4)
+    }
+FILE: KotlinInterface.kt
+    public abstract interface KotlinInterface : R|kotlin/Any| {
+        public abstract var selectedOptions: R|kotlin/Int|
+            public get(): R|kotlin/Int|
+            public set(value: R|kotlin/Int|): R|kotlin/Unit|
+
+    }

compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportWithoutPermits.kt

@@ -0,0 +1,25 @@
+// FILE: useSite.kt
+
+import C.StaticConfigurationClass.INIT_INSPECTIONS
+
+fun foo(): Int = 4
+
+// FILE: InspectionProfileImpl.java
+import static Configuration.StaticConfigurationClass
+
+public static final class C extends StaticConfigurationClass {
+    public abstract sealed class StaticConfigurationClass  {
+        public static boolean INIT_INSPECTIONS;
+    }
+}
+
+// FILE: Configuration.java
+public class Configuration implements KotlinInterface {
+    public static class StaticConfigurationClass {
+    }
+}
+
+// FILE: KotlinInterface.kt
+interface KotlinInterface {
+    var selectedOptions: Int
+}

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

@@ -45,6 +45,12 @@ public class FirLightTreeDiagnosticsTestGenerated extends AbstractFirLightTreeDi
             runTest("compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportAndPermits.kt");
         }
 
+        @Test
+        @TestMetadata("accessJavaFromKotlinViaStaticImportWithoutPermits.kt")
+        public void testAccessJavaFromKotlinViaStaticImportWithoutPermits() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportWithoutPermits.kt");
+        }
+
         @Test
         public void testAllFilesPresentInResolve() throws Exception {
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/fir/analysis-tests/testData/resolve"), Pattern.compile("^([^.]+)\\.kt$"), null, true);

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

@@ -45,6 +45,12 @@ public class FirPsiDiagnosticTestGenerated extends AbstractFirPsiDiagnosticTest
             runTest("compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportAndPermits.kt");
         }
 
+        @Test
+        @TestMetadata("accessJavaFromKotlinViaStaticImportWithoutPermits.kt")
+        public void testAccessJavaFromKotlinViaStaticImportWithoutPermits() throws Exception {
+            runTest("compiler/fir/analysis-tests/testData/resolve/accessJavaFromKotlinViaStaticImportWithoutPermits.kt");
+        }
+
         @Test
         public void testAllFilesPresentInResolve() throws Exception {
             KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/fir/analysis-tests/testData/resolve"), Pattern.compile("^([^.]+)\\.kt$"), null, true);

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/FirJavaFacade.kt

@@ -387,7 +387,7 @@ abstract class FirJavaFacade(
             if (modality == Modality.SEALED) {
                 val permittedTypes = javaClass.permittedTypes
                 setSealedClassInheritors {
-                    permittedTypes.mapNotNull { classifierType ->
+                    permittedTypes.mapNotNullTo(mutableListOf()) { classifierType ->
                         val classifier = classifierType.classifier as? JavaClass
                         classifier?.let { JavaToKotlinClassMap.mapJavaToKotlin(it.fqName!!) ?: it.classId }
                     }

compiler/javac-wrapper/src/org/jetbrains/kotlin/javac/resolve/KotlinClassifiersCache.kt

@@ -162,7 +162,7 @@ class MockKotlinClassifier(override val classId: ClassId,
     override val isEnum get() = shouldNotBeCalled()
     override val isRecord get() = shouldNotBeCalled()
     override val isSealed: Boolean get() = shouldNotBeCalled()
-    override val permittedTypes: Collection<JavaClassifierType> get() = shouldNotBeCalled()
+    override val permittedTypes: Sequence<JavaClassifierType> get() = shouldNotBeCalled()
     override val methods get() = shouldNotBeCalled()
     override val fields get() = shouldNotBeCalled()
     override val constructors get() = shouldNotBeCalled()

compiler/javac-wrapper/src/org/jetbrains/kotlin/javac/wrappers/symbols/FakeSymbolBasedClass.kt

@@ -71,7 +71,7 @@ class FakeSymbolBasedClass(
 
     override val isSealed: Boolean get() = false
 
-    override val permittedTypes: Collection<JavaClassifierType> get() = emptyList()
+    override val permittedTypes: Sequence<JavaClassifierType> get() = emptySequence()
 
     override val lightClassOriginKind: LightClassOriginKind? get() = null
 

compiler/javac-wrapper/src/org/jetbrains/kotlin/javac/wrappers/symbols/SymbolBasedClass.kt

@@ -111,8 +111,8 @@ class SymbolBasedClass(
     override val isSealed: Boolean
         get() = false
 
-    override val permittedTypes: Collection<JavaClassifierType>
+    override val permittedTypes: Sequence<JavaClassifierType>
-        get() = emptyList()
+        get() = emptySequence()
 
     override val lightClassOriginKind: LightClassOriginKind?
         get() = null

compiler/javac-wrapper/src/org/jetbrains/kotlin/javac/wrappers/trees/TreeBasedClass.kt

@@ -125,8 +125,8 @@ class TreeBasedClass(
     override val isSealed: Boolean
         get() = false
 
-    override val permittedTypes: Collection<JavaClassifierType>
+    override val permittedTypes: Sequence<JavaClassifierType>
-        get() = emptyList()
+        get() = emptySequence()
 
     override val lightClassOriginKind: LightClassOriginKind?
         get() = null

compiler/resolution.common.jvm/src/org/jetbrains/kotlin/load/java/structure/impl/JavaClassImpl.kt

@@ -19,7 +19,9 @@ package org.jetbrains.kotlin.load.java.structure.impl
 import com.intellij.openapi.diagnostic.Logger
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.psi.PsiClass
+import com.intellij.psi.PsiElementFactory
 import com.intellij.psi.PsiTypeParameter
+import com.intellij.psi.SyntaxTraverser
 import com.intellij.psi.search.SearchScope
 import org.jetbrains.kotlin.asJava.KtLightClassMarker
 import org.jetbrains.kotlin.asJava.isSyntheticValuesOrValueOfMethod
@@ -68,9 +70,18 @@ class JavaClassImpl(psiClassSource: JavaElementPsiSource<PsiClass>) : JavaClassi
     override val isSealed: Boolean
         get() = JavaElementUtil.isSealed(this)
 
-    override val permittedTypes: Collection<JavaClassifierType>
+    override val permittedTypes: Sequence<JavaClassifierType>
-        get() = psi.permitsListTypes.convertIndexed { index, _ ->
+        get() {
-            JavaClassifierTypeImpl(sourceFactory.createPermittedTypeSource(psiElementSource, index))
+            if (!isSealed) return emptySequence()
+
+            val permitsListTypes = psi.permitsListTypes
+            return if (permitsListTypes.isNotEmpty()) {
+                permitsListTypes.convertIndexed { index, _ ->
+                    JavaClassifierTypeImpl(sourceFactory.createPermittedTypeSource(psiElementSource, index))
+                }.asSequence()
+            } else {
+                lazilyComputePermittedTypesInSameFile(psiElementSource)
+            }
         }
 
     override val isRecord: Boolean
@@ -163,3 +174,19 @@ class JavaClassImpl(psiClassSource: JavaElementPsiSource<PsiClass>) : JavaClassi
         private val LOGGER = Logger.getInstance(JavaClassImpl::class.java)
     }
 }
+
+private fun lazilyComputePermittedTypesInSameFile(psiElementSource: JavaElementPsiSource<PsiClass>): Sequence<JavaClassifierType> {
+    return Sequence {
+        // Don't capture PSI directly but only via psiElementSource
+        val psi = psiElementSource.psi
+        val elementFactory = PsiElementFactory.getInstance(psi.project)
+
+        SyntaxTraverser.psiTraverser(psi.containingFile)
+            .filter(PsiClass::class.java)
+            // isInheritor can lead to resolution which can cause contract violations,
+            // that's why we compute it lazily only when the sequence is iterated.
+            .filter { it.isInheritor(psi, /* checkDeep: */ false) }
+            .map { JavaClassifierTypeImpl(psiElementSource.factory.createTypeSource(elementFactory.createType(it))) }
+            .iterator()
+    }
+}

compiler/resolution.common.jvm/src/org/jetbrains/kotlin/load/java/structure/impl/classFiles/BinaryJavaClass.kt

@@ -79,8 +79,10 @@ class BinaryJavaClass(
 
     override val lightClassOriginKind: LightClassOriginKind? get() = null
 
-    override val isSealed: Boolean get() = permittedTypes.isNotEmpty()
+    private val permittedTypesList: ArrayList<JavaClassifierType> = arrayListOf()
-    override val permittedTypes = arrayListOf<JavaClassifierType>()
+    override val isSealed: Boolean get() = permittedTypesList.isNotEmpty()
+    override val permittedTypes: Sequence<JavaClassifierType>
+        get() = permittedTypesList.asSequence()
 
     override fun isFromSourceCodeInScope(scope: SearchScope): Boolean = false
 
@@ -258,6 +260,6 @@ class BinaryJavaClass(
     }
 
     override fun visitPermittedSubclass(permittedSubclass: String?) {
-        permittedTypes.addIfNotNull(permittedSubclass?.convertInternalNameToClassifierType())
+        permittedTypesList.addIfNotNull(permittedSubclass?.convertInternalNameToClassifierType())
     }
 }

compiler/testData/diagnostics/tests/testsWithJava17/sealedClasses/javaSealedClassExhaustiveness.kt

@@ -10,11 +10,29 @@ public final class A extends Base {}
 
 // FILE: B.java
 public sealed class B extends Base permits B.C, B.D {
-    public static final class C implements B {}
+    public static final class C extends B {}
 
     public static non-sealed class D extends B {}
 }
 
+// FILE: SameFile.java
+public sealed class SameFile {
+    public static final class A extends SameFile {}
+    public static sealed class B extends SameFile {
+        public static final class C extends B {}
+        public static non-sealed class D extends B {}
+    }
+}
+
+// FILE: SameFileNonSealed.java
+public class SameFileNonSealed {
+    public static final class A extends SameFileNonSealed {}
+    public static class B extends SameFileNonSealed {
+        public static final class C extends B {}
+        public static class D extends B {}
+    }
+}
+
 // FILE: main.kt
 fun test_ok_1(base: Base) {
     val x = when (base) {
@@ -31,6 +49,21 @@ fun test_ok_2(base: Base) {
     }
 }
 
+fun test_ok_3(sameFile: SameFile) {
+    val x = when (sameFile) {
+        is SameFile.A -> 1
+        is SameFile.B -> 2
+    }
+}
+
+fun test_ok_4(sameFile: SameFile) {
+    val x = when (sameFile) {
+        is SameFile.A -> 1
+        is SameFile.B.C -> 2
+        is SameFile.B.D -> 3
+    }
+}
+
 fun test_error_1(base: Base) {
     val x = <!NO_ELSE_IN_WHEN!>when<!> (base) {
         is A -> 1
@@ -43,3 +76,31 @@ fun test_error_2(base: Base) {
         is B.C -> 2
     }
 }
+
+fun test_error_3(sameFile: SameFile) {
+    val x = <!NO_ELSE_IN_WHEN!>when<!> (sameFile) {
+        is SameFile.A -> 1
+    }
+}
+
+fun test_error_4(sameFile: SameFile) {
+    val x = <!NO_ELSE_IN_WHEN!>when<!> (sameFile) {
+        is SameFile.A -> 1
+        is SameFile.B.C -> 2
+    }
+}
+
+fun test_error_5(sameFile: SameFileNonSealed) {
+    val x = <!NO_ELSE_IN_WHEN!>when<!> (sameFile) {
+        is SameFileNonSealed.A -> 1
+        is SameFileNonSealed.B -> 2
+    }
+}
+
+fun test_error_6(sameFile: SameFileNonSealed) {
+    val x = <!NO_ELSE_IN_WHEN!>when<!> (sameFile) {
+        is SameFileNonSealed.A -> 1
+        is SameFileNonSealed.B.C -> 2
+        is SameFileNonSealed.B.D -> 2
+    }
+}

compiler/testData/diagnostics/tests/testsWithJava17/sealedClasses/javaSealedClassExhaustiveness.txt

@@ -2,8 +2,14 @@ package
 
 public fun test_error_1(/*0*/ base: Base): kotlin.Unit
 public fun test_error_2(/*0*/ base: Base): kotlin.Unit
+public fun test_error_3(/*0*/ sameFile: SameFile): kotlin.Unit
+public fun test_error_4(/*0*/ sameFile: SameFile): kotlin.Unit
+public fun test_error_5(/*0*/ sameFile: SameFileNonSealed): kotlin.Unit
+public fun test_error_6(/*0*/ sameFile: SameFileNonSealed): kotlin.Unit
 public fun test_ok_1(/*0*/ base: Base): kotlin.Unit
 public fun test_ok_2(/*0*/ base: Base): kotlin.Unit
+public fun test_ok_3(/*0*/ sameFile: SameFile): kotlin.Unit
+public fun test_ok_4(/*0*/ sameFile: SameFile): kotlin.Unit
 
 public final class A : Base {
     public constructor A()
@@ -39,3 +45,74 @@ public sealed class Base {
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
+
+public sealed class SameFile {
+    public constructor SameFile()
+    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 final class A : SameFile {
+        public constructor A()
+        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 sealed class B : SameFile {
+        public constructor B()
+        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 final class C : SameFile.B {
+            public constructor C()
+            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 D : SameFile.B {
+            public constructor D()
+            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 SameFileNonSealed {
+    public constructor SameFileNonSealed()
+    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 final class A : SameFileNonSealed {
+        public constructor A()
+        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 B : SameFileNonSealed {
+        public constructor B()
+        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 final class C : SameFileNonSealed.B {
+            public constructor C()
+            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 D : SameFileNonSealed.B {
+            public constructor D()
+            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/testData/diagnostics/tests/testsWithJava17/sealedClasses/javaSealedInterfaceExhaustiveness.kt

@@ -20,6 +20,12 @@ public enum E implements Base {
     First, Second
 }
 
+// FILE: SameFile.java
+public sealed interface SameFile {
+    public static final class A implements SameFile {}
+    public static non-sealed class B implements SameFile {}
+}
+
 // FILE: main.kt
 fun test_ok_1(base: Base) {
     val x = when (base) {
@@ -39,6 +45,13 @@ fun test_ok_2(base: Base) {
     }
 }
 
+fun test_ok_3(sameFile: SameFile) {
+    val x = when (sameFile) {
+        is SameFile.A -> 1
+        is SameFile.B -> 2
+    }
+}
+
 fun test_error_1(base: Base) {
     val x = <!NO_ELSE_IN_WHEN!>when<!> (base) {
         is A -> 1
@@ -63,3 +76,9 @@ fun test_error_3(base: Base) {
         E.Second -> 5
     }
 }
+
+fun test_error_4(sameFile: SameFile) {
+    val x = <!NO_ELSE_IN_WHEN!>when<!> (sameFile) {
+        is SameFile.A -> 1
+    }
+}

compiler/testData/diagnostics/tests/testsWithJava17/sealedClasses/javaSealedInterfaceExhaustiveness.txt

@@ -3,8 +3,10 @@ package
 public fun test_error_1(/*0*/ base: Base): kotlin.Unit
 public fun test_error_2(/*0*/ base: Base): kotlin.Unit
 public fun test_error_3(/*0*/ base: Base): kotlin.Unit
+public fun test_error_4(/*0*/ sameFile: SameFile): kotlin.Unit
 public fun test_ok_1(/*0*/ base: Base): kotlin.Unit
 public fun test_ok_2(/*0*/ base: Base): kotlin.Unit
+public fun test_ok_3(/*0*/ sameFile: SameFile): kotlin.Unit
 
 public interface A : Base {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
@@ -59,3 +61,24 @@ public final enum class E : kotlin.Enum<E!>, Base {
     public final /*synthesized*/ fun valueOf(/*0*/ value: kotlin.String): E
     public final /*synthesized*/ fun values(): kotlin.Array<E>
 }
+
+public sealed interface SameFile {
+    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 final class A : SameFile {
+        public constructor A()
+        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 B : SameFile {
+        public constructor B()
+        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
+    }
+}
+

core/compiler.common.jvm/src/org/jetbrains/kotlin/load/java/structure/javaElements.kt

@@ -102,7 +102,7 @@ interface JavaClass : JavaClassifier, JavaTypeParameterListOwner, JavaModifierLi
     val isEnum: Boolean
     val isRecord: Boolean
     val isSealed: Boolean
-    val permittedTypes: Collection<JavaClassifierType>
+    val permittedTypes: Sequence<JavaClassifierType>
     val lightClassOriginKind: LightClassOriginKind?
 
     val methods: Collection<JavaMethod>

core/descriptors.jvm/src/org/jetbrains/kotlin/load/java/lazy/descriptors/LazyJavaClassDescriptor.kt

@@ -197,7 +197,7 @@ class LazyJavaClassDescriptor(
 
     override fun getSealedSubclasses(): Collection<ClassDescriptor> = if (modality == Modality.SEALED) {
         val attributes = TypeUsage.COMMON.toAttributes()
-        jClass.permittedTypes.mapNotNull {
+        jClass.permittedTypes.mapNotNullTo(mutableListOf()) {
             c.typeResolver.transformJavaType(it, attributes).constructor.declarationDescriptor as? ClassDescriptor
         }.sortedBy { it.fqNameSafe.asString() }
     } else {

core/descriptors.jvm/src/org/jetbrains/kotlin/load/java/lazy/descriptors/SyntheticJavaClassDescriptor.kt

@@ -193,8 +193,8 @@ class SyntheticJavaClassDescriptor(
             get() = this@SyntheticJavaClassDescriptor.isRecord
         override val isSealed: Boolean
             get() = modality == Modality.SEALED
-        override val permittedTypes: Collection<JavaClassifierType>
+        override val permittedTypes: Sequence<JavaClassifierType>
-            get() = emptyList()
+            get() = emptySequence()
         override val lightClassOriginKind: LightClassOriginKind?
             get() = null
         override val methods: Collection<JavaMethod>

core/descriptors.runtime/src/org/jetbrains/kotlin/descriptors/runtime/structure/ReflectJavaClass.kt

@@ -133,10 +133,11 @@ class ReflectJavaClass(
     override val isSealed: Boolean
         get() = Java16SealedRecordLoader.loadIsSealed(klass) ?: false
 
-    override val permittedTypes: Collection<JavaClassifierType>
+    override val permittedTypes: Sequence<JavaClassifierType>
         get() = Java16SealedRecordLoader.loadGetPermittedSubclasses(klass)
             ?.map(::ReflectJavaClassifierType)
-            ?: emptyList()
+            ?.asSequence()
+            ?: emptySequence()
 
     override fun equals(other: Any?) = other is ReflectJavaClass && klass == other.klass
 

plugins/lombok/lombok.k2/src/org/jetbrains/kotlin/lombok/k2/java/dummyJavaElements.kt

@@ -75,7 +75,7 @@ class DummyJavaClass(name: String, override val fqName: FqName, numberOfTypePara
         get() = shouldNotBeCalled()
     override val isSealed: Boolean
         get() = shouldNotBeCalled()
-    override val permittedTypes: Collection<JavaClassifierType>
+    override val permittedTypes: Sequence<JavaClassifierType>
         get() = shouldNotBeCalled()
     override val lightClassOriginKind: LightClassOriginKind?
         get() = shouldNotBeCalled()