diff --git a/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ScriptGenerator.kt b/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ScriptGenerator.kt
index b85f5752dab..8459df42ad1 100644
--- a/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ScriptGenerator.kt
+++ b/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ScriptGenerator.kt
@@ -10,7 +10,6 @@ import org.jetbrains.kotlin.descriptors.ParameterDescriptor
 import org.jetbrains.kotlin.descriptors.ScriptDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
-import org.jetbrains.kotlin.ir.assertCast
 import org.jetbrains.kotlin.ir.builders.declarations.IrFunctionBuilder
 import org.jetbrains.kotlin.ir.declarations.DescriptorMetadataSource
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
@@ -197,7 +196,7 @@ class ScriptGenerator(declarationGenerator: DeclarationGenerator) : DeclarationG
                             context.irBuiltIns.unitType, IrStatementOrigin.DESTRUCTURING_DECLARATION
                         )
                         val ktInitializer = d.initializer!!
-                        val initializerExpr = ktInitializer.deparenthesize().accept(statementGenerator, null).assertCast<IrExpression>()
+                        val initializerExpr = ktInitializer.deparenthesize().accept(statementGenerator, null) as IrExpression
                         val containerValue =
                             statementGenerator.scope.createTemporaryVariableInBlock(context, initializerExpr, irBlock, "container")
 
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrElement.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrElement.kt
index 136f29f1c44..397928b29dd 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrElement.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrElement.kt
@@ -1,43 +1,24 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.ir
 
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
-import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
 interface IrElement {
     val startOffset: Int
+
     val endOffset: Int
 
     fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R
 
-    fun <D> acceptChildren(visitor: IrElementVisitor<Unit, D>, data: D): Unit
-
     fun <D> transform(transformer: IrElementTransformer<D>, data: D): IrElement =
         accept(transformer, data)
 
-    fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D): Unit
+    fun <D> acceptChildren(visitor: IrElementVisitor<Unit, D>, data: D)
+
+    fun <D> transformChildren(transformer: IrElementTransformer<D>, data: D)
 }
-
-interface IrStatement : IrElement
-
-fun IrStatement.transformStatement(transformer: IrElementTransformerVoid): IrStatement =
-    transform(transformer, null) as IrStatement
-
-inline fun <reified T : IrElement> IrElement.assertCast(): T =
-    if (this is T) this else throw AssertionError("Expected ${T::class.simpleName}: $this")
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrElements.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrElements.kt
new file mode 100644
index 00000000000..5e1f7d354e2
--- /dev/null
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrElements.kt
@@ -0,0 +1,11 @@
+/*
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.ir
+
+import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
+
+fun IrStatement.transformStatement(transformer: IrElementTransformerVoid): IrStatement =
+    transform(transformer, null) as IrStatement
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrStatement.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrStatement.kt
new file mode 100644
index 00000000000..dfb83cf93ea
--- /dev/null
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrStatement.kt
@@ -0,0 +1,8 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.ir
+
+interface IrStatement : IrElement