diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/IrBuiltInsOverFir.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/IrBuiltInsOverFir.kt
index bb72d7e409e..98b62637b94 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/IrBuiltInsOverFir.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/IrBuiltInsOverFir.kt
@@ -530,16 +530,6 @@ class IrBuiltInsOverFir(
     private val suspendFunctionNMap = mutableMapOf<Int, IrClass>()
     private val kSuspendFunctionNMap = mutableMapOf<Int, IrClass>()
 
-    override fun functionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass = functionN(arity)
-
-    override fun kFunctionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass = kFunctionN(arity)
-
-    override fun suspendFunctionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass =
-        suspendFunctionN(arity)
-
-    override fun kSuspendFunctionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass =
-        kSuspendFunctionN(arity)
-
     override fun functionN(arity: Int): IrClass = functionNMap.getOrPut(arity) {
         referenceClassByClassId(StandardNames.getFunctionClassId(arity))!!.owner
     }
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrBuiltIns.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrBuiltIns.kt
index 2969f0e012d..f58083fd274 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrBuiltIns.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrBuiltIns.kt
@@ -135,7 +135,6 @@ abstract class IrBuiltIns {
     abstract val checkNotNullSymbol: IrSimpleFunctionSymbol
     abstract val dataClassArrayMemberHashCodeSymbol: IrSimpleFunctionSymbol
     abstract val dataClassArrayMemberToStringSymbol: IrSimpleFunctionSymbol
-    abstract fun getKPropertyClass(mutable: Boolean, n: Int): IrClassSymbol
     abstract val enumClass: IrClassSymbol
 
     abstract val intPlusSymbol: IrSimpleFunctionSymbol
@@ -147,19 +146,6 @@ abstract class IrBuiltIns {
     abstract val arrayOf: IrSimpleFunctionSymbol
     abstract val arrayOfNulls: IrSimpleFunctionSymbol
 
-    abstract fun getNonBuiltInFunctionsByExtensionReceiver(
-        name: Name, vararg packageNameSegments: String
-    ): Map<IrClassifierSymbol, IrSimpleFunctionSymbol>
-
-    abstract fun getNonBuiltinFunctionsByReturnType(
-        name: Name, vararg packageNameSegments: String
-    ): Map<IrClassifierSymbol, IrSimpleFunctionSymbol>
-
-    abstract fun functionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass
-    abstract fun kFunctionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass
-    abstract fun suspendFunctionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass
-    abstract fun kSuspendFunctionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass
-
     abstract fun functionN(arity: Int): IrClass
     abstract fun kFunctionN(arity: Int): IrClass
     abstract fun suspendFunctionN(arity: Int): IrClass
@@ -170,8 +156,19 @@ abstract class IrBuiltIns {
     abstract fun findFunctions(name: Name, packageFqName: FqName): Iterable<IrSimpleFunctionSymbol>
     abstract fun findClass(name: Name, vararg packageNameSegments: String = arrayOf("kotlin")): IrClassSymbol?
     abstract fun findClass(name: Name, packageFqName: FqName): IrClassSymbol?
+
+    abstract fun getKPropertyClass(mutable: Boolean, n: Int): IrClassSymbol
+
     abstract fun findBuiltInClassMemberFunctions(builtInClass: IrClassSymbol, name: Name): Iterable<IrSimpleFunctionSymbol>
 
+    abstract fun getNonBuiltInFunctionsByExtensionReceiver(
+        name: Name, vararg packageNameSegments: String
+    ): Map<IrClassifierSymbol, IrSimpleFunctionSymbol>
+
+    abstract fun getNonBuiltinFunctionsByReturnType(
+        name: Name, vararg packageNameSegments: String
+    ): Map<IrClassifierSymbol, IrSimpleFunctionSymbol>
+
     abstract fun getBinaryOperator(name: Name, lhsType: IrType, rhsType: IrType): IrSimpleFunctionSymbol
     abstract fun getUnaryOperator(name: Name, receiverType: IrType): IrSimpleFunctionSymbol
 
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrBuiltInsOverDescriptors.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrBuiltInsOverDescriptors.kt
index 178f18b0770..1db0b78a3bd 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrBuiltInsOverDescriptors.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrBuiltInsOverDescriptors.kt
@@ -516,18 +516,6 @@ class IrBuiltInsOverDescriptors(
                 KotlinBuiltIns.isNullableAny(descriptor.valueParameters.first().type)
     }
 
-    override fun functionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass =
-        functionFactory.functionN(arity, declarator)
-
-    override fun kFunctionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass =
-        functionFactory.kFunctionN(arity, declarator)
-
-    override fun suspendFunctionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass =
-        functionFactory.suspendFunctionN(arity, declarator)
-
-    override fun kSuspendFunctionN(arity: Int, declarator: SymbolTable.((IrClassSymbol) -> IrClass) -> IrClass): IrClass =
-        functionFactory.kSuspendFunctionN(arity, declarator)
-
     override fun functionN(arity: Int): IrClass = functionFactory.functionN(arity)
     override fun kFunctionN(arity: Int): IrClass = functionFactory.kFunctionN(arity)
     override fun suspendFunctionN(arity: Int): IrClass = functionFactory.suspendFunctionN(arity)