KT-47101: Fix companion supertypes

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

@@ -25710,6 +25710,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                     runTest("compiler/testData/diagnostics/tests/scopes/classHeader/classParents.kt");
                 }
 
+                @Test
+                @TestMetadata("companionNestedVsOuter.kt")
+                public void testCompanionNestedVsOuter() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/classHeader/companionNestedVsOuter.kt");
+                }
+
                 @Test
                 @TestMetadata("companionObjectParents.kt")
                 public void testCompanionObjectParents() throws Exception {

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

@@ -25710,6 +25710,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                     runTest("compiler/testData/diagnostics/tests/scopes/classHeader/classParents.kt");
                 }
 
+                @Test
+                @TestMetadata("companionNestedVsOuter.kt")
+                public void testCompanionNestedVsOuter() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/classHeader/companionNestedVsOuter.kt");
+                }
+
                 @Test
                 @TestMetadata("companionObjectParents.kt")
                 public void testCompanionObjectParents() throws Exception {

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

@@ -25710,6 +25710,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                     runTest("compiler/testData/diagnostics/tests/scopes/classHeader/classParents.kt");
                 }
 
+                @Test
+                @TestMetadata("companionNestedVsOuter.kt")
+                public void testCompanionNestedVsOuter() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/classHeader/companionNestedVsOuter.kt");
+                }
+
                 @Test
                 @TestMetadata("companionObjectParents.kt")
                 public void testCompanionObjectParents() throws Exception {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirSupertypesResolution.kt

@@ -24,7 +24,6 @@ import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeTypeParameterSupertype
 import org.jetbrains.kotlin.fir.resolve.providers.firProvider
 import org.jetbrains.kotlin.fir.resolve.providers.symbolProvider
 import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.LocalClassesNavigationInfo
-import org.jetbrains.kotlin.fir.scopes.FirCompositeScope
 import org.jetbrains.kotlin.fir.scopes.FirScope
 import org.jetbrains.kotlin.fir.scopes.createImportingScopes
 import org.jetbrains.kotlin.fir.scopes.getNestedClassifierScope
@@ -43,6 +42,7 @@ import org.jetbrains.kotlin.fir.visitors.FirTransformer
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.types.model.TypeArgumentMarker
 import org.jetbrains.kotlin.utils.addIfNotNull
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 class FirSupertypeResolverProcessor(session: FirSession, scopeSession: ScopeSession) :
     FirTransformerBasedResolveProcessor(session, scopeSession) {
@@ -169,19 +169,22 @@ private fun FirClassLikeDeclaration.typeParametersScope(): FirScope? {
     return FirMemberTypeParameterScope(this)
 }
 
-private fun createOtherScopesForNestedClasses(
+private fun createOtherScopesForNestedClassesOrCompanion(
     klass: FirClass,
     session: FirSession,
     scopeSession: ScopeSession,
-    supertypeComputationSession: SupertypeComputationSession
+    supertypeComputationSession: SupertypeComputationSession,
+    withCompanionScopes: Boolean,
 ): Collection<FirScope> =
     mutableListOf<FirScope>().apply {
         // Note: from higher priority to lower priority
         // See also: BodyResolveContext.withScopesForClass
         addIfNotNull(session.nestedClassifierScope(klass))
-        val companionObjects = klass.declarations.filterIsInstance<FirRegularClass>().filter { it.isCompanion }
+        if (withCompanionScopes) {
-        for (companionObject in companionObjects) {
+            val companionObjects = klass.declarations.filterIsInstance<FirRegularClass>().filter { it.isCompanion }
-            addIfNotNull(session.nestedClassifierScope(companionObject))
+            for (companionObject in companionObjects) {
+                addIfNotNull(session.nestedClassifierScope(companionObject))
+            }
         }
         lookupSuperTypes(
             klass,
@@ -240,13 +243,26 @@ open class FirSupertypeResolverVisitor(
 
     private fun prepareScopeForNestedClasses(klass: FirClass): ScopePersistentList {
         return supertypeComputationSession.getOrPutScopeForNestedClasses(klass) {
-            val scopes = prepareScopes(klass)
+            calculateScopes(klass, true)
-
-            resolveAllSupertypes(klass, klass.superTypeRefs)
-            scopes.pushAll(createOtherScopesForNestedClasses(klass, session, scopeSession, supertypeComputationSession))
         }
     }
 
+    private fun prepareScopeForCompanion(klass: FirClass): ScopePersistentList {
+        return supertypeComputationSession.getOrPutScopeForCompanion(klass) {
+            calculateScopes(klass, false)
+        }
+    }
+
+    private fun calculateScopes(
+        klass: FirClass,
+        withCompanionScopes: Boolean,
+    ): PersistentList<FirScope> {
+        resolveAllSupertypes(klass, klass.superTypeRefs)
+        return prepareScopes(klass).pushAll(
+            createOtherScopesForNestedClassesOrCompanion(klass, session, scopeSession, supertypeComputationSession, withCompanionScopes)
+        )
+    }
+
     private fun resolveAllSupertypes(
         classLikeDeclaration: FirClassLikeDeclaration,
         supertypeRefs: List<FirTypeRef>,
@@ -285,6 +301,10 @@ open class FirSupertypeResolverVisitor(
                     else -> scopeForLocalClass ?: return persistentListOf()
                 }
             }
+            classLikeDeclaration.safeAs<FirRegularClass>()?.isCompanion == true -> {
+                val outerClassFir = classId.outerClassId?.let(::getFirClassifierByFqName) as? FirRegularClass
+                prepareScopeForCompanion(outerClassFir ?: return persistentListOf())
+            }
             classId.isNestedClass -> {
                 val outerClassFir = classId.outerClassId?.let(::getFirClassifierByFqName) as? FirRegularClass
                 prepareScopeForNestedClasses(outerClassFir ?: return persistentListOf())
@@ -446,6 +466,7 @@ private fun createErrorTypeRef(fir: FirElement, message: String, kind: Diagnosti
 class SupertypeComputationSession {
     private val fileScopesMap = hashMapOf<FirFile, ScopePersistentList>()
     private val scopesForNestedClassesMap = hashMapOf<FirClass, ScopePersistentList>()
+    private val scopesForCompanionMap = hashMapOf<FirClass, ScopePersistentList>()
     val supertypeStatusMap = linkedMapOf<FirClassLikeDeclaration, SupertypeComputationStatus>()
 
     val supertypesSupplier: SupertypeSupplier = object : SupertypeSupplier() {
@@ -473,6 +494,9 @@ class SupertypeComputationSession {
     fun getOrPutScopeForNestedClasses(klass: FirClass, scope: () -> ScopePersistentList): ScopePersistentList =
         scopesForNestedClassesMap.getOrPut(klass) { scope() }
 
+    fun getOrPutScopeForCompanion(klass: FirClass, scope: () -> ScopePersistentList): ScopePersistentList =
+        scopesForCompanionMap.getOrPut(klass) { scope() }
+
     fun startComputingSupertypes(classLikeDeclaration: FirClassLikeDeclaration) {
         require(supertypeStatusMap[classLikeDeclaration] == null) {
             "Unexpected in startComputingSupertypes supertype status for $classLikeDeclaration: ${supertypeStatusMap[classLikeDeclaration]}"

compiler/testData/diagnostics/tests/scopes/classHeader/companionNestedVsOuter.kt

@@ -0,0 +1,8 @@
+// FIR_IDENTICAL
+open class B
+
+class A {
+    companion object : B() { // Nested B should be invisible here but it's not
+        class B
+    }
+}

compiler/testData/diagnostics/tests/scopes/classHeader/companionNestedVsOuter.txt

@@ -0,0 +1,29 @@
+package
+
+public final class A {
+    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 companion object Companion : B {
+        private constructor Companion()
+        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 B {
+            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 open class B {
+    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
+}

compiler/testData/diagnostics/tests/scopes/classHeader/companionObjectParents.fir.kt

@@ -7,7 +7,7 @@ val bImpl: B.Companion.Interface
     get() = null!!
 
 interface A {
-    companion object : <!CYCLIC_INHERITANCE_HIERARCHY!>Nested<!>(), <!CYCLIC_INHERITANCE_HIERARCHY!>Interface<!> by aImpl, <!CYCLIC_INHERITANCE_HIERARCHY!>I<Nested, Interface><!> {
+    companion object : <!UNRESOLVED_REFERENCE!>Nested<!>(), <!UNRESOLVED_REFERENCE!>Interface<!> by aImpl, I<<!UNRESOLVED_REFERENCE!>Nested<!>, <!UNRESOLVED_REFERENCE!>Interface<!>> {
 
         class Nested
 
@@ -16,7 +16,7 @@ interface A {
 }
 
 class B {
-    companion object : <!CYCLIC_INHERITANCE_HIERARCHY!>Nested<!>(), <!CYCLIC_INHERITANCE_HIERARCHY!>Interface<!> by aImpl, <!CYCLIC_INHERITANCE_HIERARCHY!>I<Nested, Interface><!> {
+    companion object : <!UNRESOLVED_REFERENCE!>Nested<!>(), <!UNRESOLVED_REFERENCE!>Interface<!> by aImpl, I<<!UNRESOLVED_REFERENCE!>Nested<!>, <!UNRESOLVED_REFERENCE!>Interface<!>> {
 
         class Nested
 

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

@@ -25722,6 +25722,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     runTest("compiler/testData/diagnostics/tests/scopes/classHeader/classParents.kt");
                 }
 
+                @Test
+                @TestMetadata("companionNestedVsOuter.kt")
+                public void testCompanionNestedVsOuter() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/classHeader/companionNestedVsOuter.kt");
+                }
+
                 @Test
                 @TestMetadata("companionObjectParents.kt")
                 public void testCompanionObjectParents() throws Exception {