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 2afad113cb2..ca601c514e7 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
@@ -6,17 +6,22 @@
 package org.jetbrains.kotlin.backend.common.ir
 
 import org.jetbrains.kotlin.backend.common.CommonBackendContext
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.builtins.PrimitiveType
 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.util.ReferenceSymbolTable
+import org.jetbrains.kotlin.ir.util.getPackageFragment
 import org.jetbrains.kotlin.ir.util.referenceFunction
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -24,7 +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>
@@ -173,8 +178,6 @@ abstract class Symbols<out T : CommonBackendContext>(val context: T, private val
 
     abstract val coroutineSuspendedGetter: IrSimpleFunctionSymbol
 
-    abstract val lateinitIsInitializedPropertyGetter: IrSimpleFunctionSymbol
-
     fun getFunction(parameterCount: Int) = symbolTable.referenceClass(context.builtIns.getFunction(parameterCount))
 
     val functionReference = calc { symbolTable.referenceClass(context.getInternalClass("FunctionReference")) }
@@ -215,4 +218,17 @@ abstract class Symbols<out T : CommonBackendContext>(val context: T, private val
 
     val intAnd = getBinaryOperator(OperatorNameConventions.AND, builtIns.intType, builtIns.intType)
     val intPlusInt = getBinaryOperator(OperatorNameConventions.PLUS, builtIns.intType, builtIns.intType)
-}
\ No newline at end of file
+
+    companion object {
+        fun isLateinitIsInitializedPropertyGetter(symbol: IrFunctionSymbol): Boolean =
+            symbol is IrSimpleFunctionSymbol && symbol.owner.let { function ->
+                function.name.asString() == "<get-isInitialized>" &&
+                        function.parent is IrPackageFragment &&
+                        function.getPackageFragment()!!.fqName.asString() == "kotlin" &&
+                        function.valueParameters.isEmpty() &&
+                        (symbol.owner.extensionReceiverParameter?.type?.classifierOrNull?.owner as? IrClass).let { receiverClass ->
+                            receiverClass?.fqName?.toUnsafe() == KotlinBuiltIns.FQ_NAMES.kProperty0
+                        }
+            }
+    }
+}
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrUtils.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrUtils.kt
index 571ee73e41a..add2c2bd45a 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrUtils.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrUtils.kt
@@ -18,11 +18,7 @@ package org.jetbrains.kotlin.backend.common.ir
 
 import org.jetbrains.kotlin.backend.common.DumpIrTreeWithDescriptorsVisitor
 import org.jetbrains.kotlin.backend.common.deepCopyWithVariables
-import org.jetbrains.kotlin.backend.common.descriptors.WrappedClassConstructorDescriptor
-import org.jetbrains.kotlin.backend.common.descriptors.WrappedReceiverParameterDescriptor
-import org.jetbrains.kotlin.backend.common.descriptors.WrappedTypeParameterDescriptor
-import org.jetbrains.kotlin.backend.common.descriptors.WrappedValueParameterDescriptor
-import org.jetbrains.kotlin.backend.common.descriptors.WrappedVariableDescriptor
+import org.jetbrains.kotlin.backend.common.descriptors.*
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.builders.IrStatementsBuilder
@@ -32,10 +28,6 @@ import org.jetbrains.kotlin.ir.declarations.impl.IrConstructorImpl
 import org.jetbrains.kotlin.ir.declarations.impl.IrTypeParameterImpl
 import org.jetbrains.kotlin.ir.declarations.impl.IrValueParameterImpl
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
-import org.jetbrains.kotlin.ir.expressions.IrCall
-import org.jetbrains.kotlin.ir.expressions.IrExpression
-import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
-import org.jetbrains.kotlin.ir.expressions.IrFunctionReference
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.IrBlockBodyImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrDelegatingConstructorCallImpl
@@ -52,6 +44,7 @@ import org.jetbrains.kotlin.ir.util.defaultType
 import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.ir.util.patchDeclarationParents
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import java.io.StringWriter
 
@@ -392,3 +385,13 @@ fun isElseBranch(branch: IrBranch) = branch is IrElseBranch || ((branch.conditio
 fun IrSimpleFunction.isMethodOfAny() =
     ((valueParameters.size == 0 && name.asString().let { it == "hashCode" || it == "toString" }) ||
             (valueParameters.size == 1 && name.asString() == "equals" && valueParameters[0].type.isNullableAny()))
+
+val IrClass.fqName: FqName?
+    get() {
+        val parentFqName = when (val parent = parent) {
+            is IrPackageFragment -> parent.fqName
+            is IrClass -> parent.fqName
+            else -> return null
+        }
+        return parentFqName?.child(name)
+    }
diff --git a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LateinitLowering.kt b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LateinitLowering.kt
index 44d9a049a12..23d2ad4e412 100644
--- a/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LateinitLowering.kt
+++ b/compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LateinitLowering.kt
@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.backend.common.lower
 
 import org.jetbrains.kotlin.backend.common.CommonBackendContext
 import org.jetbrains.kotlin.backend.common.FileLoweringPass
+import org.jetbrains.kotlin.backend.common.ir.Symbols
 import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
@@ -82,7 +83,7 @@ class LateinitLowering(val context: CommonBackendContext) : FileLoweringPass {
             override fun visitCall(expression: IrCall): IrExpression {
                 expression.transformChildrenVoid(this)
 
-                if (expression.symbol != context.ir.symbols.lateinitIsInitializedPropertyGetter) return expression
+                if (!Symbols.isLateinitIsInitializedPropertyGetter(expression.symbol)) return expression
 
                 val receiver = expression.extensionReceiver as IrPropertyReference
 
@@ -133,4 +134,4 @@ class LateinitLowering(val context: CommonBackendContext) : FileLoweringPass {
         }
 
     private val throwErrorFunction by lazy { context.ir.symbols.ThrowUninitializedPropertyAccessException.owner }
-}
\ No newline at end of file
+}
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt
index 12bb25b715f..72af6c30ceb 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt
@@ -24,12 +24,14 @@ import org.jetbrains.kotlin.ir.SourceRangeInfo
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.backend.js.lower.CallableReferenceKey
 import org.jetbrains.kotlin.ir.backend.js.lower.ConstructorPair
-import org.jetbrains.kotlin.ir.backend.js.lower.inline.ModuleIndex
 import org.jetbrains.kotlin.ir.backend.js.utils.OperatorNames
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.IrFileImpl
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
-import org.jetbrains.kotlin.ir.symbols.*
+import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
+import org.jetbrains.kotlin.ir.symbols.IrEnumEntrySymbol
+import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
+import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.types.impl.IrDynamicTypeImpl
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.name.FqName
@@ -184,15 +186,6 @@ class JsIrBackendContext(
                         NoLookupLocation.FROM_BACKEND
                     ).filterNot { it.isExpect }.single().getter!!
                 )
-
-            override val lateinitIsInitializedPropertyGetter =
-                symbolTable.referenceSimpleFunction(
-                    module.getPackage(kotlinPackageFqn).memberScope.getContributedVariables(
-                        Name.identifier("isInitialized"), NoLookupLocation.FROM_BACKEND
-                    ).single {
-                        it.extensionReceiverParameter != null && !it.isExternal
-                    }.getter!!
-                )
         }
 
         override fun shouldGenerateHandlerParameterForDefaultBodyFun() = true
@@ -244,8 +237,6 @@ class JsIrBackendContext(
             return vars.single()
         }
 
-    val lateinitIsInitializedPropertyGetter = ir.symbols.lateinitIsInitializedPropertyGetter
-
     val captureStackSymbol = symbolTable.referenceSimpleFunction(getInternalFunctions("captureStack").single())
     val newThrowableSymbol = symbolTable.referenceSimpleFunction(getInternalFunctions("newThrowable").single())
 
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/inline/FunctionInlining.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/inline/FunctionInlining.kt
index 4e7134ba436..202da42315e 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/inline/FunctionInlining.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/inline/FunctionInlining.kt
@@ -7,8 +7,12 @@
 
 package org.jetbrains.kotlin.ir.backend.js.lower.inline
 
-import org.jetbrains.kotlin.backend.common.*
+import org.jetbrains.kotlin.backend.common.IrElementTransformerVoidWithContext
+import org.jetbrains.kotlin.backend.common.ScopeWithIr
+import org.jetbrains.kotlin.backend.common.ir.Symbols
 import org.jetbrains.kotlin.backend.common.ir.createTemporaryVariableWithWrappedDescriptor
+import org.jetbrains.kotlin.backend.common.isBuiltInIntercepted
+import org.jetbrains.kotlin.backend.common.isBuiltInSuspendCoroutineUninterceptedOrReturn
 import org.jetbrains.kotlin.backend.common.lower.CoroutineIntrinsicLambdaOrigin
 import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.backend.common.serialization.fqNameSafe
@@ -56,7 +60,7 @@ internal class FunctionInlining(val context: Context): IrElementTransformerVoidW
 
         val languageVersionSettings = context.configuration.languageVersionSettings
         when {
-            callSite.symbol == context.ir.symbols.lateinitIsInitializedPropertyGetter ->
+            Symbols.isLateinitIsInitializedPropertyGetter(callSite.symbol) ->
                 return callSite
             // Handle coroutine intrinsics
             // TODO These should actually be inlined.
@@ -432,4 +436,4 @@ internal class FunctionInlining(val context: Context): IrElementTransformerVoidW
             return evaluationStatements
         }
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmBackendContext.kt b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmBackendContext.kt
index 682d02e2c9e..4831709ad9a 100644
--- a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmBackendContext.kt
+++ b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmBackendContext.kt
@@ -143,14 +143,6 @@ class JvmBackendContext(
             override val coroutineSuspendedGetter: IrSimpleFunctionSymbol
                 get() = TODO("not implemented") //To change initializer of created properties use File | Settings | File Templates.
 
-            override val lateinitIsInitializedPropertyGetter = symbolTable.referenceSimpleFunction(
-                state.module.getPackage(FqName("kotlin")).memberScope.getContributedVariables(
-                    Name.identifier("isInitialized"), NoLookupLocation.FROM_BACKEND
-                ).single {
-                    it.extensionReceiverParameter != null && !it.isExternal
-                }.getter!!
-            )
-
             val lambdaClass = calc { symbolTable.referenceClass(context.getInternalClass("Lambda")) }
 
             fun getKFunction(parameterCount: Int) = symbolTable.referenceClass(reflectionTypes.getKFunction(parameterCount))
diff --git a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/BridgeLowering.kt b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/BridgeLowering.kt
index e8f602e5c19..7588d94014b 100644
--- a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/BridgeLowering.kt
+++ b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/BridgeLowering.kt
@@ -18,13 +18,16 @@ import org.jetbrains.kotlin.backend.common.lower.irNot
 import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
 import org.jetbrains.kotlin.backend.jvm.JvmLoweredDeclarationOrigin
-import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.IrFunctionImpl
 import org.jetbrains.kotlin.ir.declarations.impl.IrValueParameterImpl
-import org.jetbrains.kotlin.ir.expressions.*
+import org.jetbrains.kotlin.ir.expressions.IrConstKind
+import org.jetbrains.kotlin.ir.expressions.IrExpression
+import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin
 import org.jetbrains.kotlin.ir.expressions.impl.IrCallImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrConstImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
@@ -32,13 +35,16 @@ import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 import org.jetbrains.kotlin.ir.symbols.impl.IrSimpleFunctionSymbolImpl
 import org.jetbrains.kotlin.ir.symbols.impl.IrValueParameterSymbolImpl
-import org.jetbrains.kotlin.ir.types.*
+import org.jetbrains.kotlin.ir.types.IrErrorType
+import org.jetbrains.kotlin.ir.types.IrSimpleType
+import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.impl.IrSimpleTypeImpl
 import org.jetbrains.kotlin.ir.types.impl.IrStarProjectionImpl
-import org.jetbrains.kotlin.ir.util.*
+import org.jetbrains.kotlin.ir.util.defaultType
+import org.jetbrains.kotlin.ir.util.isInterface
+import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.utils.DFS
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 import org.jetbrains.org.objectweb.asm.commons.Method
 
@@ -454,25 +460,6 @@ private data class SignatureWithSource(val signature: Method, val source: IrSimp
     }
 }
 
-val IrClass.fqName
-    get(): FqName? {
-        val parentFqName = when (val parent = parent) {
-            is IrPackageFragment -> parent.fqName
-            is IrClass -> parent.fqName
-            else -> return null
-        }
-        return parentFqName?.child(name)
-    }
-
-fun IrClass.isSubclassOf(pred: (IrClass) -> Boolean): Boolean =
-    DFS.ifAny(
-        listOf(this),
-        DFS.Neighbors { current ->
-            current.superTypes.mapNotNull { (it as? IrSimpleType)?.classifier?.owner as? IrClass }
-        },
-        pred
-    )
-
 fun IrSimpleFunction.allOverridden(): Sequence<IrSimpleFunction> {
     val visited = mutableSetOf<IrSimpleFunction>()