diff --git a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/Generator.kt b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/Generator.kt
index 43f71a65cc8..3a07da78394 100644
--- a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/Generator.kt
+++ b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/Generator.kt
@@ -143,7 +143,6 @@ class Generator(
         println()
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     private fun SmartPrinter.printImports() {
         val imports = buildList {
             addAll(configuration.additionalCheckers.values)
diff --git a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/DiagnosticGroup.kt b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/DiagnosticGroup.kt
index f6c245cd309..195c081c5df 100644
--- a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/DiagnosticGroup.kt
+++ b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/DiagnosticGroup.kt
@@ -43,7 +43,6 @@ abstract class AbstractDiagnosticGroup @PrivateForInline constructor(val name: S
     ) = deprecationDiagnosticDelegateProvider<P>(featureForError, positioningStrategy, init)
 
     @PrivateForInline
-    @OptIn(ExperimentalStdlibApi::class)
     internal inline fun <reified P : PsiElement> diagnosticDelegateProvider(
         severity: Severity,
         positioningStrategy: PositioningStrategy,
@@ -61,7 +60,6 @@ abstract class AbstractDiagnosticGroup @PrivateForInline constructor(val name: S
     }
 
     @PrivateForInline
-    @OptIn(ExperimentalStdlibApi::class)
     internal inline fun <reified P : PsiElement> deprecationDiagnosticDelegateProvider(
         featureForError: LanguageFeature,
         positioningStrategy: PositioningStrategy,
diff --git a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/DiagnosticList.kt b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/DiagnosticList.kt
index 913aafb0303..74fa5490470 100644
--- a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/DiagnosticList.kt
+++ b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/DiagnosticList.kt
@@ -115,7 +115,7 @@ sealed class DiagnosticBuilder(
     @PrivateForInline
     val parameters = mutableListOf<DiagnosticParameter>()
 
-    @OptIn(PrivateForInline::class, ExperimentalStdlibApi::class)
+    @OptIn(PrivateForInline::class)
     inline fun <reified T> parameter(name: String) {
         if (parameters.size >= MAX_DIAGNOSTIC_PARAMETER_COUNT) {
             error("Diagnostic cannot have more than $MAX_DIAGNOSTIC_PARAMETER_COUNT parameters")
diff --git a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/ErrorListDiagnosticListRenderer.kt b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/ErrorListDiagnosticListRenderer.kt
index ad4d57c07e7..c561155393d 100644
--- a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/ErrorListDiagnosticListRenderer.kt
+++ b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/model/ErrorListDiagnosticListRenderer.kt
@@ -74,7 +74,6 @@ object ErrorListDiagnosticListRenderer : DiagnosticListRenderer() {
         println()
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     private fun SmartPrinter.printPositioningStrategyAndLanguageFeature(diagnostic: DiagnosticData) {
         val argumentsList = buildList {
             if (diagnostic is DeprecationDiagnosticData) {
@@ -88,7 +87,6 @@ object ErrorListDiagnosticListRenderer : DiagnosticListRenderer() {
     }
 
 
-    @OptIn(ExperimentalStdlibApi::class)
     private fun DiagnosticData.getAllTypeArguments(): List<KType> = buildList {
         add(psiType)
         parameters.mapTo(this) { it.type }
@@ -131,7 +129,6 @@ object ErrorListDiagnosticListRenderer : DiagnosticListRenderer() {
         println()
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     private fun collectImports(
         diagnosticList: DiagnosticList,
         packageName: String,
diff --git a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/utils.kt b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/utils.kt
index 9344520885b..55fa3316ead 100644
--- a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/utils.kt
+++ b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/utils.kt
@@ -16,7 +16,6 @@ fun getGenerationPath(rootPath: File, packageName: String): File =
         .apply { mkdirs() }
 
 
-@OptIn(ExperimentalStdlibApi::class)
 fun KType.collectClassNamesTo(set: MutableSet<String>) {
     (classifier as? KClass<*>)?.qualifiedName?.let(set::add)
     for (argument in arguments) {
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/ConeTypeCompatibilityChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/ConeTypeCompatibilityChecker.kt
index 068fb10a45a..d3a63e41e1c 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/ConeTypeCompatibilityChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/ConeTypeCompatibilityChecker.kt
@@ -321,7 +321,6 @@ object ConeTypeCompatibilityChecker {
     }
 
     /** Converts type arguments in a [ConeClassLikeType] to a [TypeArgumentMapping]. */
-    @OptIn(ExperimentalStdlibApi::class)
     private fun ConeClassLikeType.toTypeArgumentMapping(
         ctx: ConeInferenceContext,
         envMapping: Map<FirTypeParameterSymbol, BoundTypeArgument> = emptyMap(),
@@ -443,7 +442,6 @@ object ConeTypeCompatibilityChecker {
             firClass.resolvedSuperTypes.mapNotNull { (it as? ConeClassLikeType)?.lookupTag?.toFirClassWithSuperClasses(ctx) }.toSet()
         }
 
-        @OptIn(ExperimentalStdlibApi::class)
         val thisAndAllSuperClasses: Set<FirClassWithSuperClasses> by lazy {
             val queue = ArrayDeque<FirClassWithSuperClasses>()
             queue.addLast(this)
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirImplementationMismatchChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirImplementationMismatchChecker.kt
index b3e845c77d7..b61ac7ef36e 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirImplementationMismatchChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirImplementationMismatchChecker.kt
@@ -186,7 +186,6 @@ object FirImplementationMismatchChecker : FirClassChecker() {
         reporter.reportOn(containingClass.source, FirErrors.VAR_OVERRIDDEN_BY_VAL_BY_DELEGATION, symbol, overriddenVar, context)
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     private fun checkConflictingMembers(
         containingClass: FirClass,
         context: CheckerContext,
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirOperatorModifierChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirOperatorModifierChecker.kt
index e5d44566d63..bb9587265ec 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirOperatorModifierChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirOperatorModifierChecker.kt
@@ -159,7 +159,6 @@ private object Checks {
 
 }
 
-@OptIn(ExperimentalStdlibApi::class)
 private object OperatorFunctionChecks {
 
     //reimplementation of org.jetbrains.kotlin.util.OperatorChecks for FIR
diff --git a/compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeAttributes.kt b/compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeAttributes.kt
index 869f197be84..01a2ff30ab0 100644
--- a/compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeAttributes.kt
+++ b/compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeAttributes.kt
@@ -92,7 +92,6 @@ class ConeAttributes private constructor(attributes: List<ConeAttribute<*>>) : A
         return arrayMap[index] != null
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     operator fun plus(attribute: ConeAttribute<*>): ConeAttributes {
         if (attribute in this) return this
         if (isEmpty()) return predefinedAttributes[attribute] ?: ConeAttributes(attribute)
diff --git a/compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/FirElementSerializer.kt b/compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/FirElementSerializer.kt
index 88c8dc5885f..145bcd93bea 100644
--- a/compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/FirElementSerializer.kt
+++ b/compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/FirElementSerializer.kt
@@ -214,7 +214,6 @@ class FirElementSerializer private constructor(
         return builder
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     private fun FirClass.declarations(): List<FirCallableDeclaration> = buildList {
         val memberScope =
             defaultType().scope(session, scopeSession, FakeOverrideTypeCalculator.DoNothing)
diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DataClassMembersGenerator.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DataClassMembersGenerator.kt
index bdd019c264b..7cf435d7220 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DataClassMembersGenerator.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DataClassMembersGenerator.kt
@@ -199,7 +199,6 @@ class DataClassMembersGenerator(val components: Fir2IrComponents) : Fir2IrCompon
                 withForcedTypeCalculator = true
             )
             val contributedFunctionsInSupertypes =
-                @OptIn(ExperimentalStdlibApi::class)
                 buildMap<Name, FirSimpleFunction> {
                     for (name in listOf(EQUALS, HASHCODE_NAME, TO_STRING)) {
                         // We won't synthesize a function if there is a user-contributed one.
diff --git a/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/FirJavaElementFinder.kt b/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/FirJavaElementFinder.kt
index ce4588c9c1b..86b92b094e9 100644
--- a/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/FirJavaElementFinder.kt
+++ b/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/FirJavaElementFinder.kt
@@ -47,7 +47,6 @@ class FirJavaElementFinder(
 ) : PsiElementFinder(), KotlinFinderMarker {
     private val psiManager = PsiManager.getInstance(project)
 
-    @OptIn(ExperimentalStdlibApi::class)
     private val firProviders: List<FirProvider> = buildList {
         add(session.firProvider)
         session.collectAllDependentSourceSessions().mapTo(this) { it.firProvider }
diff --git a/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/scopes/JavaClassStaticUseSiteScope.kt b/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/scopes/JavaClassStaticUseSiteScope.kt
index 5fe55a60e7d..31b2a2ee7b4 100644
--- a/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/scopes/JavaClassStaticUseSiteScope.kt
+++ b/compiler/fir/java/src/org/jetbrains/kotlin/fir/java/scopes/JavaClassStaticUseSiteScope.kt
@@ -79,7 +79,6 @@ class JavaClassStaticUseSiteScope internal constructor(
         return result
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     override fun getCallableNames(): Set<Name> {
         return buildSet {
             addAll(declaredMemberScope.getCallableNames())
@@ -89,7 +88,6 @@ class JavaClassStaticUseSiteScope internal constructor(
         }
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     override fun getClassifierNames(): Set<Name> {
         return buildSet {
             addAll(declaredMemberScope.getClassifierNames())
diff --git a/compiler/fir/modularized-tests/tests/org/jetbrains/kotlin/fir/AbstractFullPipelineModularizedTest.kt b/compiler/fir/modularized-tests/tests/org/jetbrains/kotlin/fir/AbstractFullPipelineModularizedTest.kt
index 39a9d42604e..0417008cea4 100644
--- a/compiler/fir/modularized-tests/tests/org/jetbrains/kotlin/fir/AbstractFullPipelineModularizedTest.kt
+++ b/compiler/fir/modularized-tests/tests/org/jetbrains/kotlin/fir/AbstractFullPipelineModularizedTest.kt
@@ -312,8 +312,7 @@ abstract class AbstractFullPipelineModularizedTest : AbstractModularizedTest() {
             val initMeasurement = measurements.filterIsInstance<CompilerInitializationMeasurement>().firstOrNull()
             val irMeasurements = measurements.filterIsInstance<IRMeasurement>()
 
-            @OptIn(ExperimentalStdlibApi::class)
-            val components = buildMap<String, Long> {
+            val components = buildMap {
                 put("Init", initMeasurement?.milliseconds ?: 0)
                 put("Analysis", analysisMeasurement?.milliseconds ?: 0)
 
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirSymbolProvider.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirSymbolProvider.kt
index 74774a8c31d..61b361d4a60 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirSymbolProvider.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/FirSymbolProvider.kt
@@ -28,7 +28,7 @@ annotation class FirSymbolProviderInternals
 abstract class FirSymbolProvider(val session: FirSession) : FirSessionComponent {
     abstract fun getClassLikeSymbolByClassId(classId: ClassId): FirClassLikeSymbol<*>?
 
-    @OptIn(ExperimentalStdlibApi::class, FirSymbolProviderInternals::class)
+    @OptIn(FirSymbolProviderInternals::class)
     open fun getTopLevelCallableSymbols(packageFqName: FqName, name: Name): List<FirCallableSymbol<*>> {
         return buildList { getTopLevelCallableSymbolsTo(this, packageFqName, name) }
     }
@@ -36,7 +36,7 @@ abstract class FirSymbolProvider(val session: FirSession) : FirSessionComponent
     @FirSymbolProviderInternals
     abstract fun getTopLevelCallableSymbolsTo(destination: MutableList<FirCallableSymbol<*>>, packageFqName: FqName, name: Name)
 
-    @OptIn(ExperimentalStdlibApi::class, FirSymbolProviderInternals::class)
+    @OptIn(FirSymbolProviderInternals::class)
     open fun getTopLevelFunctionSymbols(packageFqName: FqName, name: Name): List<FirNamedFunctionSymbol> {
         return buildList { getTopLevelFunctionSymbolsTo(this, packageFqName, name) }
     }
@@ -44,7 +44,7 @@ abstract class FirSymbolProvider(val session: FirSession) : FirSessionComponent
     @FirSymbolProviderInternals
     abstract fun getTopLevelFunctionSymbolsTo(destination: MutableList<FirNamedFunctionSymbol>, packageFqName: FqName, name: Name)
 
-    @OptIn(ExperimentalStdlibApi::class, FirSymbolProviderInternals::class)
+    @OptIn(FirSymbolProviderInternals::class)
     open fun getTopLevelPropertySymbols(packageFqName: FqName, name: Name): List<FirPropertySymbol> {
         return buildList { getTopLevelPropertySymbolsTo(this, packageFqName, name) }
     }
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirDependenciesSymbolProviderImpl.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirDependenciesSymbolProviderImpl.kt
index 9aceeb2072e..cdea686381c 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirDependenciesSymbolProviderImpl.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/providers/impl/FirDependenciesSymbolProviderImpl.kt
@@ -45,17 +45,17 @@ open class FirDependenciesSymbolProviderImpl(session: FirSession) : FirDependenc
         }
     }
 
-    @OptIn(FirSymbolProviderInternals::class, ExperimentalStdlibApi::class)
+    @OptIn(FirSymbolProviderInternals::class)
     private fun computeTopLevelCallables(callableId: CallableId): List<FirCallableSymbol<*>> = buildList {
         dependencyProviders.forEach { it.getTopLevelCallableSymbolsTo(this, callableId.packageName, callableId.callableName) }
     }
 
-    @OptIn(FirSymbolProviderInternals::class, ExperimentalStdlibApi::class)
+    @OptIn(FirSymbolProviderInternals::class)
     private fun computeTopLevelFunctions(callableId: CallableId): List<FirNamedFunctionSymbol> = buildList {
         dependencyProviders.forEach { it.getTopLevelFunctionSymbolsTo(this, callableId.packageName, callableId.callableName) }
     }
 
-    @OptIn(FirSymbolProviderInternals::class, ExperimentalStdlibApi::class)
+    @OptIn(FirSymbolProviderInternals::class)
     private fun computeTopLevelProperties(callableId: CallableId): List<FirPropertySymbol> = buildList {
         dependencyProviders.forEach { it.getTopLevelPropertySymbolsTo(this, callableId.packageName, callableId.callableName) }
     }
diff --git a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/impl/FirDelegatedMemberScope.kt b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/impl/FirDelegatedMemberScope.kt
index 02c612f2f59..64a82716200 100644
--- a/compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/impl/FirDelegatedMemberScope.kt
+++ b/compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/impl/FirDelegatedMemberScope.kt
@@ -172,7 +172,6 @@ class FirDelegatedMemberScope(
         }
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     private val callableNamesLazy: Set<Name> by lazy(LazyThreadSafetyMode.PUBLICATION) {
         buildSet {
             addAll(declaredMemberScope.getCallableNames())
@@ -183,7 +182,6 @@ class FirDelegatedMemberScope(
         }
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     private val classifierNamesLazy: Set<Name> by lazy(LazyThreadSafetyMode.PUBLICATION) {
         buildSet {
             addAll(declaredMemberScope.getClassifierNames())
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/SuperCalls.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/SuperCalls.kt
index ad5dfdb0988..797ad0fcc68 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/SuperCalls.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/SuperCalls.kt
@@ -126,7 +126,6 @@ private inline fun BodyResolveComponents.resolveSupertypesByMembers(
     }
 }
 
-@OptIn(ExperimentalStdlibApi::class)
 private fun BodyResolveComponents.getFunctionMembers(type: ConeKotlinType, name: Name): Collection<FirCallableDeclaration> =
     buildList {
         type.scope(session, scopeSession, FakeOverrideTypeCalculator.DoNothing)?.processFunctionsByName(name) {
@@ -134,7 +133,6 @@ private fun BodyResolveComponents.getFunctionMembers(type: ConeKotlinType, name:
         }
     }
 
-@OptIn(ExperimentalStdlibApi::class)
 private fun BodyResolveComponents.getPropertyMembers(type: ConeKotlinType, name: Name): Collection<FirCallableDeclaration> =
     buildList {
         type.scope(session, scopeSession, FakeOverrideTypeCalculator.DoNothing)?.processPropertiesByName(name) {
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirTowerResolveTask.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirTowerResolveTask.kt
index fb632a27a91..d180d8cd895 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirTowerResolveTask.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirTowerResolveTask.kt
@@ -30,7 +30,6 @@ internal class TowerDataElementsForName(
     val nonLocalTowerDataElements = towerDataContext.nonLocalTowerDataElements.asReversedFrozen()
 
     val reversedFilteredLocalScopes by lazy(LazyThreadSafetyMode.NONE) {
-        @OptIn(ExperimentalStdlibApi::class)
         buildList {
             val localScopesBase = towerDataContext.localScopes
             val lastIndex = localScopesBase.lastIndex
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/ConeConstraintSystemUtilContext.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/ConeConstraintSystemUtilContext.kt
index 0421e0ca70c..04eaa844934 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/ConeConstraintSystemUtilContext.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/ConeConstraintSystemUtilContext.kt
@@ -58,7 +58,6 @@ object ConeConstraintSystemUtilContext : ConstraintSystemUtilContext {
         return ConeFixVariableConstraintPosition(variable) as FixVariableConstraintPosition<T>
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     override fun extractLambdaParameterTypesFromDeclaration(declaration: PostponedAtomWithRevisableExpectedType): List<ConeKotlinType?>? {
         require(declaration is PostponedResolvedAtom)
         return when (declaration) {
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirWhenExhaustivenessTransformer.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirWhenExhaustivenessTransformer.kt
index 569d90e8076..668a92b5abe 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirWhenExhaustivenessTransformer.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirWhenExhaustivenessTransformer.kt
@@ -35,7 +35,6 @@ class FirWhenExhaustivenessTransformer(private val bodyResolveComponents: BodyRe
             WhenOnNothingExhaustivenessChecker
         )
 
-        @OptIn(ExperimentalStdlibApi::class)
         fun computeAllMissingCases(session: FirSession, whenExpression: FirWhenExpression): List<WhenMissingCase> {
             val subjectType = getSubjectType(session, whenExpression) ?: return emptyList()
             return buildList {
@@ -59,7 +58,6 @@ class FirWhenExhaustivenessTransformer(private val bodyResolveComponents: BodyRe
         }
 
 
-        @OptIn(ExperimentalStdlibApi::class)
         private fun getCheckers(
             subjectType: ConeKotlinType,
             session: FirSession
@@ -102,7 +100,6 @@ class FirWhenExhaustivenessTransformer(private val bodyResolveComponents: BodyRe
         return whenExpression
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     private fun processExhaustivenessCheck(whenExpression: FirWhenExpression) {
         if (whenExpression.branches.any { it.condition is FirElseIfTrueCondition }) {
             whenExpression.replaceExhaustivenessStatus(ExhaustivenessStatus.ProperlyExhaustive)
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt
index 5b94796e03f..68886691873 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt
@@ -1190,7 +1190,6 @@ open class FirExpressionsResolveTransformer(transformer: FirBodyResolveTransform
         }
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     override fun transformAugmentedArraySetCall(
         augmentedArraySetCall: FirAugmentedArraySetCall,
         data: ResolutionMode
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/mpp/FirExpectActualResolver.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/mpp/FirExpectActualResolver.kt
index 679e30a4027..807e9be17b9 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/mpp/FirExpectActualResolver.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/mpp/FirExpectActualResolver.kt
@@ -36,7 +36,6 @@ import org.jetbrains.kotlin.utils.keysToMap
 import java.util.*
 
 object FirExpectActualResolver {
-    @OptIn(ExperimentalStdlibApi::class)
     fun findExpectForActual(
         actualSymbol: FirBasedSymbol<*>,
         useSiteSession: FirSession,
@@ -668,7 +667,6 @@ object FirExpectActualResolver {
         }
     }
 
-    @OptIn(ExperimentalStdlibApi::class)
     private fun FirTypeScope.getMembersTo(
         destination: MutableList<in FirCallableSymbol<*>>,
         name: Name,
diff --git a/compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraph.kt b/compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraph.kt
index c68ba1f5684..7a8262a58b5 100644
--- a/compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraph.kt
+++ b/compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraph.kt
@@ -171,7 +171,6 @@ enum class EdgeKind(
     DeadBackward(usedInDfa = false, usedInDeadDfa = false, usedInCfa = true, isBack = true, isDead = true)
 }
 
-@OptIn(ExperimentalStdlibApi::class)
 private fun ControlFlowGraph.orderNodes(): LinkedHashSet<CFGNode<*>> {
     val visitedNodes = linkedSetOf<CFGNode<*>>()
     /*
@@ -203,7 +202,6 @@ private fun ControlFlowGraph.orderNodes(): LinkedHashSet<CFGNode<*>> {
     return visitedNodes
 }
 
-@OptIn(ExperimentalStdlibApi::class)
 private fun ControlFlowGraph.walkThrowSubGraphs(
     otherGraph: ControlFlowGraph,
     visitedNodes: Set<CFGNode<*>>,