[FIR] Properly report SEALED_INHERITOR_IN_DIFFERENT_MODULE

^KT-46031 Fixed
^KT-59804 Fixed

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

@@ -1083,6 +1083,12 @@ public class FirOldFrontendMPPDiagnosticsWithLightTreeTestGenerated extends Abst
         public void testKt45796() throws Exception {
             runTest("compiler/testData/diagnostics/tests/multiplatform/exhaustiveness/kt45796.kt");
         }
+
+        @Test
+        @TestMetadata("sealedHierarchyInBambooMppStructure.kt")
+        public void testSealedHierarchyInBambooMppStructure() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/multiplatform/exhaustiveness/sealedHierarchyInBambooMppStructure.kt");
+        }
     }
 
     @Nested

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

@@ -1083,6 +1083,12 @@ public class FirOldFrontendMPPDiagnosticsWithPsiTestGenerated extends AbstractFi
         public void testKt45796() throws Exception {
             runTest("compiler/testData/diagnostics/tests/multiplatform/exhaustiveness/kt45796.kt");
         }
+
+        @Test
+        @TestMetadata("sealedHierarchyInBambooMppStructure.kt")
+        public void testSealedHierarchyInBambooMppStructure() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/multiplatform/exhaustiveness/sealedHierarchyInBambooMppStructure.kt");
+        }
     }
 
     @Nested

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirSealedSupertypeChecker.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.fir.declarations.FirAnonymousObject
 import org.jetbrains.kotlin.fir.declarations.FirClass
 import org.jetbrains.kotlin.fir.declarations.FirDeclarationOrigin
 import org.jetbrains.kotlin.fir.declarations.utils.classId
+import org.jetbrains.kotlin.fir.declarations.utils.isExpect
 import org.jetbrains.kotlin.fir.declarations.utils.isSealed
 import org.jetbrains.kotlin.fir.declarations.utils.modality
 import org.jetbrains.kotlin.fir.resolve.providers.symbolProvider
@@ -51,8 +52,7 @@ object FirSealedSupertypeChecker : FirClassChecker() {
             if (superClassPackage != subclassPackage) {
                 reporter.reportOn(superTypeRef.source, FirErrors.SEALED_INHERITOR_IN_DIFFERENT_PACKAGE, context)
             }
-            if (superClass.moduleData != declaration.moduleData) {
+            if (superClass.moduleData != declaration.moduleData && !superClass.isExpect) {
-                // TODO, KT-59804: implement logic like in org.jetbrains.kotlin.resolve.checkers.SealedInheritorInSameModuleChecker for MPP support.
                 reporter.reportOn(superTypeRef.source, FirErrors.SEALED_INHERITOR_IN_DIFFERENT_MODULE, context)
             }
         }

compiler/testData/diagnostics/tests/multiplatform/exhaustiveness/sealedHierarchyInBambooMppStructure.fir.kt

@@ -0,0 +1,29 @@
+// LANGUAGE: +MultiPlatformProjects
+// ISSUE: KT-46031
+
+// MODULE: common-a
+// TARGET_PLATFORM: Common
+
+expect sealed class Base()
+class A : Base() // OK, A in same module with Base
+
+// MODULE: common-b()()(common-a)
+// TARGET_PLATFORM: Common
+
+class B : Base() // OK, B inherits `expect` class, not `actual`
+
+// MODULE: common-c()()(common-b)
+// TARGET_PLATFORM: Common
+
+actual sealed class Base actual constructor()
+class C : Base() // OK, C in same module with actual Base
+
+// MODULE: common-d()()(common-c)
+// TARGET_PLATFORM: Common
+
+class D : <!SEALED_INHERITOR_IN_DIFFERENT_MODULE!>Base<!>() // Error, D not in same module with actual Base
+
+// MODULE: jvm()()(common-d)
+// TARGET_PLATFORM: JVM
+
+class E : <!SEALED_INHERITOR_IN_DIFFERENT_MODULE!>Base<!>() // Error, E not in same module with actual Base

compiler/testData/diagnostics/tests/multiplatform/exhaustiveness/sealedHierarchyInBambooMppStructure.kt

@@ -0,0 +1,29 @@
+// LANGUAGE: +MultiPlatformProjects
+// ISSUE: KT-46031
+
+// MODULE: common-a
+// TARGET_PLATFORM: Common
+
+expect sealed <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE{COMMON}, EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE{COMMON}!>class Base<!>()
+class A : Base() // OK, A in same module with Base
+
+// MODULE: common-b()()(common-a)
+// TARGET_PLATFORM: Common
+
+class B : Base() // OK, B inherits `expect` class, not `actual`
+
+// MODULE: common-c()()(common-b)
+// TARGET_PLATFORM: Common
+
+actual sealed <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE, EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE{COMMON}!>class Base<!> actual constructor()
+class C : Base() // OK, C in same module with actual Base
+
+// MODULE: common-d()()(common-c)
+// TARGET_PLATFORM: Common
+
+class D : <!SEALED_INHERITOR_IN_DIFFERENT_MODULE!>Base<!>() // Error, D not in same module with actual Base
+
+// MODULE: jvm()()(common-d)
+// TARGET_PLATFORM: JVM
+
+class E : <!SEALED_INHERITOR_IN_DIFFERENT_MODULE!>Base<!>() // Error, E not in same module with actual Base

compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis/sealedInheritorsInComplexModuleStructure.fir.kt

@@ -12,7 +12,7 @@ expect sealed class SealedWithPlatformActuals : SealedWithSharedActual
 package foo
 
 actual sealed class SealedWithSharedActual
-class SimpleShared : <!SEALED_INHERITOR_IN_DIFFERENT_MODULE, UNRESOLVED_REFERENCE!>SealedWithPlatformActuals<!>()
+class SimpleShared : <!UNRESOLVED_REFERENCE!>SealedWithPlatformActuals<!>()
 
 // MODULE: main()()(intermediate)
 // TARGET_PLATFORM: JVM

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

@@ -23952,6 +23952,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 public void testKt45796() throws Exception {
                     runTest("compiler/testData/diagnostics/tests/multiplatform/exhaustiveness/kt45796.kt");
                 }
+
+                @Test
+                @TestMetadata("sealedHierarchyInBambooMppStructure.kt")
+                public void testSealedHierarchyInBambooMppStructure() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/exhaustiveness/sealedHierarchyInBambooMppStructure.kt");
+                }
             }
 
             @Nested