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 fddf2a8cfb8..96f85e0e283 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
@@ -1,4 +1,4 @@
- /*
+/*
  * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
  * that can be found in the license/LICENSE.txt file.
  */
@@ -12,14 +12,13 @@ import org.jetbrains.kotlin.builtins.UnsignedType
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.findClassAcrossModuleDependencies
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
-import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.declarations.IrPackageFragment
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
-import org.jetbrains.kotlin.ir.types.classifierOrNull
+import org.jetbrains.kotlin.ir.types.classOrNull
 import org.jetbrains.kotlin.ir.util.ReferenceSymbolTable
 import org.jetbrains.kotlin.ir.util.fqNameWhenAvailable
 import org.jetbrains.kotlin.ir.util.getPackageFragment
@@ -30,7 +29,7 @@ import org.jetbrains.kotlin.resolve.calls.components.isVararg
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.util.OperatorNameConventions
 
- // This is what Context collects about IR.
+// This is what Context collects about IR.
 abstract class Ir<out T : CommonBackendContext>(val context: T, val irModule: IrModuleFragment) {
 
     abstract val symbols: Symbols<T>
@@ -192,7 +191,7 @@ abstract class Symbols<out T : CommonBackendContext>(val context: T, private val
                         function.parent is IrPackageFragment &&
                         function.getPackageFragment()!!.fqName.asString() == "kotlin" &&
                         function.valueParameters.isEmpty() &&
-                        (symbol.owner.extensionReceiverParameter?.type?.classifierOrNull?.owner as? IrClass).let { receiverClass ->
+                        symbol.owner.extensionReceiverParameter?.type?.classOrNull?.owner.let { receiverClass ->
                             receiverClass?.fqNameWhenAvailable?.toUnsafe() == KotlinBuiltIns.FQ_NAMES.kProperty0
                         }
             }
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/InnerClassesLowering.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/InnerClassesLowering.kt
index f7728090912..afb8ba6dfb6 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/InnerClassesLowering.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/InnerClassesLowering.kt
@@ -20,7 +20,7 @@ import org.jetbrains.kotlin.ir.expressions.impl.*
 import org.jetbrains.kotlin.ir.symbols.IrConstructorSymbol
 import org.jetbrains.kotlin.ir.symbols.IrValueParameterSymbol
 import org.jetbrains.kotlin.ir.symbols.IrValueSymbol
-import org.jetbrains.kotlin.ir.types.classifierOrNull
+import org.jetbrains.kotlin.ir.types.classOrNull
 import org.jetbrains.kotlin.ir.util.dump
 import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.ir.util.patchDeclarationParents
@@ -39,7 +39,7 @@ class InnerClassesLowering(val context: BackendContext) : ClassLoweringPass {
         // TODO: is this the correct way to get the class?
         // -1 means value is either IMPLICIT or EXTENSION receiver
         get() = if (this is IrValueParameterSymbol && owner.index == -1 && owner.name.isSpecial /* <this> */)
-            owner.type.classifierOrNull?.owner as IrClass
+            owner.type.classOrNull?.owner
         else
             null
 
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/ir/util/IrTypeUtils.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/ir/util/IrTypeUtils.kt
index f0f3dae7a16..c473198f060 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/ir/util/IrTypeUtils.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/ir/util/IrTypeUtils.kt
@@ -54,7 +54,7 @@ fun IrType.isFunctionTypeOrSubtype(): Boolean = DFS.ifAny(listOf(this), { it.sup
 
 fun IrType.isTypeParameter() = classifierOrNull is IrTypeParameterSymbol
 
-fun IrType.isInterface() = (classifierOrNull?.owner as? IrClass)?.kind == ClassKind.INTERFACE
+fun IrType.isInterface() = classOrNull?.owner?.kind == ClassKind.INTERFACE
 
 fun IrType.isFunctionOrKFunction() = isFunction() || isKFunction()
 
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/irTypes.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/irTypes.kt
index 863b34b7f5d..2875cc30062 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/irTypes.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/irTypes.kt
@@ -44,6 +44,9 @@ val IrType.classifierOrFail: IrClassifierSymbol
 val IrType.classifierOrNull: IrClassifierSymbol?
     get() = safeAs<IrSimpleType>()?.classifier
 
+val IrType.classOrNull: IrClassSymbol?
+    get() = classifierOrNull as? IrClassSymbol
+
 fun IrType.makeNotNull() =
     if (this is IrSimpleType && this.hasQuestionMark) {
         IrSimpleTypeImpl(
@@ -82,7 +85,7 @@ fun IrType.toKotlinType(): KotlinType {
 }
 
 fun IrType.getClass(): IrClass? =
-    (this.classifierOrNull as? IrClassSymbol)?.owner
+    classOrNull?.owner
 
 fun IrClassSymbol.createType(hasQuestionMark: Boolean, arguments: List<IrTypeArgument>): IrSimpleType =
     IrSimpleTypeImpl(