diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/providers/LLFirCombinedJavaSymbolProvider.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/providers/LLFirCombinedJavaSymbolProvider.kt
index 5a7781ad26b..e02ed6881c6 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/providers/LLFirCombinedJavaSymbolProvider.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/providers/LLFirCombinedJavaSymbolProvider.kt
@@ -51,7 +51,7 @@ internal class LLFirCombinedJavaSymbolProvider private constructor(
     private val classCache: NullableCaffeineCache<ClassId, FirRegularClassSymbol> = NullableCaffeineCache { it.maximumSize(2500) }
 
     override val symbolNamesProvider: FirSymbolNamesProvider = object : FirSymbolNamesProviderWithoutCallables() {
-        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String>? = null
+        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name>? = null
         override fun mayHaveTopLevelClassifier(classId: ClassId): Boolean = true
     }
 
diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/providers/LLFirCombinedSyntheticFunctionSymbolProvider.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/providers/LLFirCombinedSyntheticFunctionSymbolProvider.kt
index bc04e4bfe67..c5f714788f3 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/providers/LLFirCombinedSyntheticFunctionSymbolProvider.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/providers/LLFirCombinedSyntheticFunctionSymbolProvider.kt
@@ -35,7 +35,7 @@ internal class LLFirCombinedSyntheticFunctionSymbolProvider private constructor(
         // `FirCompositeSymbolNamesProvider` defines `mayHaveSyntheticFunctionTypes` and `mayHaveSyntheticFunctionType` correctly, which is
         // needed for consistency should this symbol provider be part of another composite symbol provider.
         object : FirCompositeSymbolNamesProvider(providers.map { it.symbolNamesProvider }) {
-            override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> = emptySet()
+            override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> = emptySet()
             override fun getPackageNamesWithTopLevelCallables(): Set<String> = emptySet()
             override fun getTopLevelCallableNamesInPackage(packageFqName: FqName): Set<Name> = emptySet()
         }
diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/resolve/extensions/LLFirResolveExtensionTool.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/resolve/extensions/LLFirResolveExtensionTool.kt
index fe89684f955..4dfbe2f8f5e 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/resolve/extensions/LLFirResolveExtensionTool.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/resolve/extensions/LLFirResolveExtensionTool.kt
@@ -75,11 +75,9 @@ private class LLFirResolveExtensionToolSymbolNamesProvider(
     private val packageFilter: LLFirResolveExtensionToolPackageFilter,
     private val fileProvider: LLFirResolveExtensionsFileProvider,
 ) : FirSymbolNamesProvider() {
-    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> = forbidAnalysis {
+    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> = forbidAnalysis {
         if (!packageFilter.packageExists(packageFqName)) return emptySet()
-        fileProvider.getFilesByPackage(packageFqName)
-            .flatMap { it.getTopLevelClassifierNames() }
-            .mapTo(mutableSetOf()) { it.asString() }
+        fileProvider.getFilesByPackage(packageFqName).flatMap { it.getTopLevelClassifierNames() }.toSet()
     }
 
     override fun getPackageNamesWithTopLevelCallables(): Set<String> = forbidAnalysis {
diff --git a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/util/LLFirKotlinSymbolNamesProvider.kt b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/util/LLFirKotlinSymbolNamesProvider.kt
index f4ad20e4d1c..0ba34319555 100644
--- a/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/util/LLFirKotlinSymbolNamesProvider.kt
+++ b/analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/util/LLFirKotlinSymbolNamesProvider.kt
@@ -25,12 +25,10 @@ internal open class LLFirKotlinSymbolNamesProvider(
     private val declarationProvider: KotlinDeclarationProvider,
     private val allowKotlinPackage: Boolean? = null,
 ) : FirSymbolNamesProvider() {
-    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> {
+    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> {
         if (allowKotlinPackage == false && packageFqName.isKotlinPackage()) return emptySet()
 
-        return declarationProvider
-            .getTopLevelKotlinClassLikeDeclarationNamesInPackage(packageFqName)
-            .mapToSetOrEmpty { it.asString() }
+        return declarationProvider.getTopLevelKotlinClassLikeDeclarationNamesInPackage(packageFqName)
     }
 
     override fun getPackageNamesWithTopLevelCallables(): Set<String>? {
diff --git a/compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/session/NativeForwardDeclarationsSymbolProvider.kt b/compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/session/NativeForwardDeclarationsSymbolProvider.kt
index bfce0d737a5..1aaaca724e8 100644
--- a/compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/session/NativeForwardDeclarationsSymbolProvider.kt
+++ b/compiler/fir/entrypoint/src/org/jetbrains/kotlin/fir/session/NativeForwardDeclarationsSymbolProvider.kt
@@ -62,11 +62,11 @@ class NativeForwardDeclarationsSymbolProvider(
         }
     }
 
-    private val includedForwardDeclarationsByPackage: Map<FqName, Set<String>> by lazy {
-        buildMap<FqName, MutableSet<String>> {
+    private val includedForwardDeclarationsByPackage: Map<FqName, Set<Name>> by lazy {
+        buildMap<FqName, MutableSet<Name>> {
             for (classId in includedForwardDeclarations) {
                 getOrPut(classId.packageFqName) { mutableSetOf() }
-                    .add(classId.shortClassName.asString())
+                    .add(classId.shortClassName)
             }
         }
     }
@@ -157,7 +157,7 @@ class NativeForwardDeclarationsSymbolProvider(
     }
 
     override val symbolNamesProvider: FirSymbolNamesProvider = object : FirSymbolNamesProviderWithoutCallables() {
-        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> =
+        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> =
             includedForwardDeclarationsByPackage[packageFqName].orEmpty()
     }
 }
diff --git a/compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/deserialization/AbstractFirDeserializedSymbolProvider.kt b/compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/deserialization/AbstractFirDeserializedSymbolProvider.kt
index 091c9fbd1d6..641e1d69e6d 100644
--- a/compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/deserialization/AbstractFirDeserializedSymbolProvider.kt
+++ b/compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/deserialization/AbstractFirDeserializedSymbolProvider.kt
@@ -94,8 +94,11 @@ abstract class AbstractFirDeserializedSymbolProvider(
     }
 
     override val symbolNamesProvider: FirSymbolNamesProvider = object : FirCachedSymbolNamesProvider(session) {
-        override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<String>? {
-            val classesInPackage = knownTopLevelClassesInPackage(packageFqName) ?: return null
+        override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<Name>? {
+            val classesInPackage = knownTopLevelClassesInPackage(packageFqName)
+                ?.mapTo(mutableSetOf()) { Name.identifier(it) }
+                ?.ifEmpty { emptySet() }
+                ?: return null
 
             if (packageFqName.asString() !in packageNamesForNonClassDeclarations) return classesInPackage
 
@@ -104,7 +107,7 @@ abstract class AbstractFirDeserializedSymbolProvider(
 
             return buildSet {
                 addAll(classesInPackage)
-                typeAliasNames.mapTo(this) { it.asString() }
+                addAll(typeAliasNames)
             }
         }
 
diff --git a/compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirBuiltinSymbolProvider.kt b/compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirBuiltinSymbolProvider.kt
index 7ad50e7a5ac..5797402ac02 100644
--- a/compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirBuiltinSymbolProvider.kt
+++ b/compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirBuiltinSymbolProvider.kt
@@ -88,9 +88,9 @@ open class FirBuiltinSymbolProvider(
         override fun getPackageNamesWithTopLevelCallables(): Set<String> =
             allPackageFragments.keys.mapTo(mutableSetOf()) { it.asString() }
 
-        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> =
+        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> =
             allPackageFragments[packageFqName]?.flatMapTo(mutableSetOf()) { fragment ->
-                fragment.classDataFinder.allClassIds.map { it.shortClassName.asString() }
+                fragment.classDataFinder.allClassIds.map { it.shortClassName }
             }.orEmpty()
 
         override fun getTopLevelCallableNamesInPackage(packageFqName: FqName): Set<Name> =
diff --git a/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaSymbolProvider.kt b/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaSymbolProvider.kt
index c19ab2c2a7c..2aeaf964a44 100644
--- a/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaSymbolProvider.kt
+++ b/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaSymbolProvider.kt
@@ -71,8 +71,10 @@ open class JavaSymbolProvider(
     override fun getPackage(fqName: FqName): FqName? = javaFacade.getPackage(fqName)
 
     override val symbolNamesProvider: FirSymbolNamesProvider = object : FirSymbolNamesProviderWithoutCallables() {
-        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String>? =
+        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name>? =
             javaFacade.knownClassNamesInPackage(packageFqName)
+                ?.mapTo(mutableSetOf()) { Name.identifier(it) }
+                ?.ifEmpty { emptySet() }
     }
 }
 
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/extensions/FirExtensionDeclarationsSymbolProvider.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/extensions/FirExtensionDeclarationsSymbolProvider.kt
index b6ec042d557..d3060a4da35 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/extensions/FirExtensionDeclarationsSymbolProvider.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/extensions/FirExtensionDeclarationsSymbolProvider.kt
@@ -64,12 +64,13 @@ class FirExtensionDeclarationsSymbolProvider private constructor(
             )
         }
 
-    private val classNamesInPackageCache: FirLazyValue<Map<FqName, Set<String>>> =
+    private val classNamesInPackageCache: FirLazyValue<Map<FqName, Set<Name>>> =
         cachesFactory.createLazyValue {
             computeNamesGroupedByPackage(
                 FirDeclarationGenerationExtension::getTopLevelClassIds,
-                ClassId::packageFqName
-            ) { it.shortClassName.asString() }
+                ClassId::packageFqName,
+                ClassId::shortClassName,
+            )
         }
 
     private fun <I, N> computeNamesGroupedByPackage(
@@ -148,7 +149,7 @@ class FirExtensionDeclarationsSymbolProvider private constructor(
     // ------------------------------------------ provider methods ------------------------------------------
 
     override val symbolNamesProvider: FirSymbolNamesProvider = object : FirSymbolNamesProvider() {
-        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> =
+        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> =
             classNamesInPackageCache.getValue()[packageFqName] ?: emptySet()
 
         override fun getPackageNamesWithTopLevelCallables(): Set<String> =
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/extensions/FirSwitchableExtensionDeclarationsSymbolProvider.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/extensions/FirSwitchableExtensionDeclarationsSymbolProvider.kt
index 1a9dc0e4ac2..ff5dfc4b37a 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/extensions/FirSwitchableExtensionDeclarationsSymbolProvider.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/extensions/FirSwitchableExtensionDeclarationsSymbolProvider.kt
@@ -38,7 +38,7 @@ class FirSwitchableExtensionDeclarationsSymbolProvider private constructor(
         override fun getPackageNamesWithTopLevelCallables(): Set<String>? =
             if (disabled) null else delegate.symbolNamesProvider.getPackageNamesWithTopLevelCallables()
 
-        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String>? =
+        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name>? =
             if (disabled) null else delegate.symbolNamesProvider.getTopLevelClassifierNamesInPackage(packageFqName)
 
         override fun getTopLevelCallableNamesInPackage(packageFqName: FqName): Set<Name>? =
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirCachedSymbolNamesProvider.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirCachedSymbolNamesProvider.kt
index c1d8c120f2e..ba53ea37079 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirCachedSymbolNamesProvider.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirCachedSymbolNamesProvider.kt
@@ -18,7 +18,7 @@ import org.jetbrains.kotlin.name.Name
  * A [FirSymbolNamesProvider] that caches all name sets.
  */
 abstract class FirCachedSymbolNamesProvider(protected val session: FirSession) : FirSymbolNamesProvider() {
-    abstract fun computeTopLevelClassifierNames(packageFqName: FqName): Set<String>?
+    abstract fun computeTopLevelClassifierNames(packageFqName: FqName): Set<Name>?
     abstract fun computePackageNamesWithTopLevelCallables(): Set<String>?
     abstract fun computeTopLevelCallableNames(packageFqName: FqName): Set<Name>?
 
@@ -32,7 +32,7 @@ abstract class FirCachedSymbolNamesProvider(protected val session: FirSession) :
     private val topLevelCallableNamesByPackage =
         session.firCachesFactory.createCache(::computeTopLevelCallableNames)
 
-    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String>? =
+    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name>? =
         topLevelClassifierNamesByPackage.getValue(packageFqName)
 
     override fun getPackageNamesWithTopLevelCallables(): Set<String>? = topLevelCallablePackageNames
@@ -49,7 +49,7 @@ class FirDelegatingCachedSymbolNamesProvider(
     session: FirSession,
     private val delegate: FirSymbolNamesProvider,
 ) : FirCachedSymbolNamesProvider(session) {
-    override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<String>? =
+    override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<Name>? =
         delegate.getTopLevelClassifierNamesInPackage(packageFqName)
 
     override fun computePackageNamesWithTopLevelCallables(): Set<String>? =
@@ -68,7 +68,7 @@ open class FirCompositeCachedSymbolNamesProvider(
     session: FirSession,
     val providers: List<FirSymbolNamesProvider>,
 ) : FirCachedSymbolNamesProvider(session) {
-    override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<String>? =
+    override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<Name>? =
         providers.flatMapToNullableSet { it.getTopLevelClassifierNamesInPackage(packageFqName) }
 
     override fun computePackageNamesWithTopLevelCallables(): Set<String>? =
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirSymbolNamesProvider.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirSymbolNamesProvider.kt
index e210f92d9f5..acc635f0e61 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirSymbolNamesProvider.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirSymbolNamesProvider.kt
@@ -32,7 +32,7 @@ abstract class FirSymbolNamesProvider {
      * All usages must take into account that the result might not include `kotlin.FunctionN` (and others for which a [FunctionTypeKind]
      * exists).
      */
-    abstract fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String>?
+    abstract fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name>?
 
     /**
      * Returns the set of fully qualified package names which contain a top-level callable declaration within the provider's scope.
@@ -96,16 +96,16 @@ abstract class FirSymbolNamesProvider {
     }
 }
 
-private fun Set<String>.mayContainTopLevelClassifier(shortClassName: Name): Boolean {
+private fun Set<Name>.mayContainTopLevelClassifier(shortClassName: Name): Boolean {
     // Symbol providers can potentially provide symbols for special names. Hence, special names have to be allowed.
-    return shortClassName.isSpecial || shortClassName.asString() in this
+    return shortClassName.isSpecial || shortClassName in this
 }
 
 /**
  * A [FirSymbolNamesProvider] for symbol providers which can't provide any symbol name sets.
  */
 object FirNullSymbolNamesProvider : FirSymbolNamesProvider() {
-    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String>? = null
+    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name>? = null
     override fun getTopLevelCallableNamesInPackage(packageFqName: FqName): Set<Name>? = null
     override fun getPackageNamesWithTopLevelCallables(): Set<String>? = null
     override fun mayHaveTopLevelClassifier(classId: ClassId): Boolean = true
@@ -116,7 +116,7 @@ object FirNullSymbolNamesProvider : FirSymbolNamesProvider() {
  * A [FirSymbolNamesProvider] for symbol providers which don't contain *any* symbols.
  */
 object FirEmptySymbolNamesProvider : FirSymbolNamesProvider() {
-    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> = emptySet()
+    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> = emptySet()
     override fun getTopLevelCallableNamesInPackage(packageFqName: FqName): Set<Name> = emptySet()
     override fun getPackageNamesWithTopLevelCallables(): Set<String> = emptySet()
     override fun mayHaveTopLevelClassifier(classId: ClassId): Boolean = false
@@ -130,7 +130,7 @@ abstract class FirSymbolNamesProviderWithoutCallables : FirSymbolNamesProvider()
 }
 
 open class FirCompositeSymbolNamesProvider(val providers: List<FirSymbolNamesProvider>) : FirSymbolNamesProvider() {
-    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String>? {
+    override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name>? {
         return providers.flatMapToNullableSet { it.getTopLevelClassifierNamesInPackage(packageFqName) }
     }
 
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirCachingCompositeSymbolProvider.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirCachingCompositeSymbolProvider.kt
index f9f84b2af8b..1675118ad81 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirCachingCompositeSymbolProvider.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirCachingCompositeSymbolProvider.kt
@@ -43,7 +43,7 @@ class FirCachingCompositeSymbolProvider(
         session,
         providers.map { it.symbolNamesProvider },
     ) {
-        override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<String>? =
+        override fun computeTopLevelClassifierNames(packageFqName: FqName): Set<Name>? =
             super.computeTopLevelClassifierNames(packageFqName).also {
                 ensureNotNull(it) { "classifier names in package $packageFqName" }
             }
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirExtensionSyntheticFunctionInterfaceProvider.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirExtensionSyntheticFunctionInterfaceProvider.kt
index 1d36b011b8b..6aa51468f2d 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirExtensionSyntheticFunctionInterfaceProvider.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirExtensionSyntheticFunctionInterfaceProvider.kt
@@ -92,7 +92,7 @@ abstract class FirSyntheticFunctionInterfaceProviderBase(
 
         override fun mayHaveSyntheticFunctionType(classId: ClassId): Boolean = classId.getAcceptableFunctionTypeKind() != null
 
-        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> =
+        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> =
             // Generated function type names aren't included in the top-level classifier names set.
             emptySet()
 
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirCloneableSymbolProvider.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirCloneableSymbolProvider.kt
index 47860742b73..9d0039a0f06 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirCloneableSymbolProvider.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirCloneableSymbolProvider.kt
@@ -79,9 +79,9 @@ class FirCloneableSymbolProvider(
     }
 
     override val symbolNamesProvider: FirSymbolNamesProvider = object : FirSymbolNamesProviderWithoutCallables() {
-        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> =
+        override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> =
             if (packageFqName == StandardClassIds.Cloneable.packageFqName) {
-                setOf(StandardClassIds.Cloneable.shortClassName.asString())
+                setOf(StandardClassIds.Cloneable.shortClassName)
             } else emptySet()
     }
 
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirProviderImpl.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirProviderImpl.kt
index 40d4d4e42d2..b46f73024b1 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirProviderImpl.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirProviderImpl.kt
@@ -85,8 +85,8 @@ class FirProviderImpl(val session: FirSession, val kotlinScopeProvider: FirKotli
             override fun getPackageNamesWithTopLevelCallables(): Set<String> =
                 state.allSubPackages.mapTo(mutableSetOf()) { it.asString() }
 
-            override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<String> =
-                state.classifierInPackage[packageFqName].orEmpty().mapTo(mutableSetOf()) { it.asString() }
+            override fun getTopLevelClassifierNamesInPackage(packageFqName: FqName): Set<Name> =
+                state.classifierInPackage[packageFqName].orEmpty()
 
             override fun getTopLevelCallableNamesInPackage(packageFqName: FqName): Set<Name> = buildSet {
                 for (key in state.functionMap.keys) {