diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/Ir.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/Ir.kt
index 7b2714265e7..25dc9d83bab 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/Ir.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/Ir.kt
@@ -118,22 +118,30 @@ open class BuiltinSymbolsBase(protected val irBuiltIns: IrBuiltIns, protected va
         .getContributedFunctions(Name.identifier("getProgressionLastElement"), NoLookupLocation.FROM_BACKEND)
         .filter { it.containingDeclaration !is BuiltInsPackageFragment }
         .map { d ->
-            val c = d.returnType?.constructor?.declarationDescriptor?.let { symbolTable.referenceClassifier(it) }
-            val f = symbolTable.referenceSimpleFunction(d)
-            c to f
+            val klass = d.returnType?.constructor?.declarationDescriptor?.let { symbolTable.referenceClassifier(it) }
+            val function = symbolTable.referenceSimpleFunction(d)
+            klass to function
         }.toMap()
 
     val toUIntByExtensionReceiver = builtInsPackage("kotlin").getContributedFunctions(
         Name.identifier("toUInt"),
         NoLookupLocation.FROM_BACKEND
     ).filter { it.containingDeclaration !is BuiltInsPackageFragment && it.extensionReceiverParameter != null }
-        .map { Pair(it.extensionReceiverParameter!!.type, symbolTable.referenceSimpleFunction(it)) }.toMap()
+        .map {
+            val klass = symbolTable.referenceClassifier(it.extensionReceiverParameter!!.type.constructor.declarationDescriptor!!)
+            val function = symbolTable.referenceSimpleFunction(it)
+            klass to function
+        }.toMap()
 
     val toULongByExtensionReceiver = builtInsPackage("kotlin").getContributedFunctions(
         Name.identifier("toULong"),
         NoLookupLocation.FROM_BACKEND
     ).filter { it.containingDeclaration !is BuiltInsPackageFragment && it.extensionReceiverParameter != null }
-        .map { Pair(it.extensionReceiverParameter!!.type, symbolTable.referenceSimpleFunction(it)) }.toMap()
+        .map {
+            val klass = symbolTable.referenceClassifier(it.extensionReceiverParameter!!.type.constructor.declarationDescriptor!!)
+            val function = symbolTable.referenceSimpleFunction(it)
+            klass to function
+        }.toMap()
 
     val any = symbolTable.referenceClass(builtIns.any)
     val unit = symbolTable.referenceClass(builtIns.unit)
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/loops/ProgressionType.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/loops/ProgressionType.kt
index f06867fb295..8e933751237 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/loops/ProgressionType.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/loops/ProgressionType.kt
@@ -201,7 +201,7 @@ internal class UIntProgressionType(symbols: Symbols<CommonBackendContext>) :
         // Uses `getProgressionLastElement(UInt, UInt, Int): UInt`
         getProgressionLastElementFunction = symbols.getProgressionLastElementByReturnType[symbols.uInt!!],
         unsignedType = symbols.uInt!!.defaultType,
-        unsignedConversionFunction = symbols.toUIntByExtensionReceiver.getValue(symbols.int.defaultType.toKotlinType())
+        unsignedConversionFunction = symbols.toUIntByExtensionReceiver.getValue(symbols.int)
     ) {
     override fun DeclarationIrBuilder.minValueExpression() = irInt(UInt.MIN_VALUE.toInt())
 
@@ -219,7 +219,7 @@ internal class ULongProgressionType(symbols: Symbols<CommonBackendContext>) :
         // Uses `getProgressionLastElement(ULong, ULong, Long): ULong`
         getProgressionLastElementFunction = symbols.getProgressionLastElementByReturnType[symbols.uLong!!],
         unsignedType = symbols.uLong!!.defaultType,
-        unsignedConversionFunction = symbols.toULongByExtensionReceiver.getValue(symbols.long.defaultType.toKotlinType())
+        unsignedConversionFunction = symbols.toULongByExtensionReceiver.getValue(symbols.long)
     ) {
     override fun DeclarationIrBuilder.minValueExpression() = irLong(ULong.MIN_VALUE.toLong())