Make descriptor-based API in ir:tree more granular

compiler/fir/fir2ir/jvm-backend/src/org/jetbrains/kotlin/fir/backend/jvm/FirJvmBackendClassResolver.kt

@@ -11,9 +11,11 @@ import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.fir.backend.Fir2IrComponents
 import org.jetbrains.kotlin.fir.resolve.firSymbolProvider
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.org.objectweb.asm.Type
 
 class FirJvmBackendClassResolver(val components: Fir2IrComponents) : JvmBackendClassResolver {
+    @DescriptorBasedIr
     override fun resolveToClassDescriptors(type: Type): List<ClassDescriptor> {
         if (type.sort != Type.OBJECT) return emptyList()
 

compiler/fir/fir2ir/jvm-backend/src/org/jetbrains/kotlin/fir/backend/jvm/FirJvmClassCodegen.kt

@@ -30,6 +30,7 @@ import org.jetbrains.kotlin.fir.types.ConeKotlinErrorType
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.fir.types.FirTypeRef
 import org.jetbrains.kotlin.fir.types.coneTypeUnsafe
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrField
 import org.jetbrains.kotlin.ir.declarations.IrFunction
@@ -96,6 +97,7 @@ class FirJvmClassCodegen(
         }
     }
 
+    @OptIn(DescriptorBasedIr::class)
     override fun generateKotlinMetadataAnnotation() {
 
         val localDelegatedProperties = (irClass.attributeOwnerId as? IrClass)?.let(context.localDelegatedProperties::get)

compiler/fir/fir2ir/jvm-backend/src/org/jetbrains/kotlin/fir/backend/jvm/FirJvmSerializerExtension.kt

@@ -23,6 +23,7 @@ import org.jetbrains.kotlin.fir.serialization.FirElementSerializer
 import org.jetbrains.kotlin.fir.serialization.FirSerializerExtension
 import org.jetbrains.kotlin.fir.serialization.nonSourceAnnotations
 import org.jetbrains.kotlin.fir.types.*
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.load.java.JvmAbi
 import org.jetbrains.kotlin.load.kotlin.NON_EXISTENT_CLASS_NAME
@@ -75,6 +76,7 @@ class FirJvmSerializerExtension @JvmOverloads constructor(
         return classBuilderMode != ClassBuilderMode.ABI || nestedClass.effectiveVisibility != FirEffectiveVisibilityImpl.Private
     }
 
+    @OptIn(DescriptorBasedIr::class)
     override fun serializeClass(
         klass: FirClass<*>,
         proto: ProtoBuf.Class.Builder,

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.fir.scopes.impl.FirClassSubstitutionScope
 import org.jetbrains.kotlin.fir.symbols.*
 import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.types.*
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.*
@@ -45,6 +46,7 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedContainerSource
 
+@OptIn(DescriptorBasedIr::class)
 class Fir2IrDeclarationStorage(
     private val components: Fir2IrComponents,
     private val moduleDescriptor: FirModuleDescriptor,

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/DataClassMembersGenerator.kt

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.fir.types.impl.FirImplicitNullableAnyTypeRef
 import org.jetbrains.kotlin.fir.types.impl.FirImplicitStringTypeRef
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.IrGeneratorContextBase
 import org.jetbrains.kotlin.ir.declarations.*
@@ -50,6 +51,7 @@ import org.jetbrains.kotlin.name.Name
  * fir own logic that traverses class hierarchies in fir elements. Also, this one creates and passes IR elements, instead of providing how
  * to declare them, to [DataClassMembersGenerator].
  */
+@OptIn(DescriptorBasedIr::class)
 class DataClassMembersGenerator(val components: Fir2IrComponents) {
 
     fun generateInlineClassMembers(klass: FirClass<*>, irClass: IrClass): List<Name> =

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/symbols/Fir2IrBindableSymbol.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.fir.symbols
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.SourceElement
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.descriptors.*
 import org.jetbrains.kotlin.ir.symbols.IrBindableSymbol
@@ -36,6 +37,7 @@ abstract class Fir2IrBindableSymbol<out D : DeclarationDescriptor, B : IrSymbolO
     override val isBound: Boolean
         get() = _owner != null
 
+    @DescriptorBasedIr
     override val descriptor: D by lazy {
         when (val owner = owner) {
             is IrEnumEntry -> WrappedEnumEntryDescriptor().apply { bind(owner) }

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/AbstractClosureAnnotator.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.backend.common
 
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrFunction
@@ -30,6 +31,7 @@ import java.util.*
 
 class Closure(val capturedValues: List<ValueDescriptor>)
 
+@OptIn(DescriptorBasedIr::class)
 abstract class AbstractClosureAnnotator : IrElementVisitorVoid {
     protected abstract fun recordFunctionClosure(functionDescriptor: FunctionDescriptor, closure: Closure)
     protected abstract fun recordClassClosure(classDescriptor: ClassDescriptor, closure: Closure)

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/DeepCopyIrTreeWithDeclarations.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.backend.common
 
 import org.jetbrains.kotlin.descriptors.VariableDescriptor
 import org.jetbrains.kotlin.descriptors.impl.LocalVariableDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.IrVariable
 import org.jetbrains.kotlin.ir.descriptors.WrappedVariableDescriptor
@@ -29,6 +30,7 @@ import org.jetbrains.kotlin.ir.util.DescriptorsRemapper
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
 
 @Suppress("UNCHECKED_CAST")
+@OptIn(DescriptorBasedIr::class)
 fun <T : IrElement> T.deepCopyWithVariables(): T {
     val descriptorsRemapper = object : DescriptorsRemapper {
         override fun remapDeclaredVariable(descriptor: VariableDescriptor) = WrappedVariableDescriptor()

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/DescriptorsToIrRemapper.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.backend.common
 
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.descriptors.*
@@ -50,6 +51,7 @@ object DescriptorsToIrRemapper : DescriptorsRemapper {
             WrappedValueParameterDescriptor(descriptor.annotations, descriptor.source)
 }
 
+@OptIn(DescriptorBasedIr::class)
 object WrappedDescriptorPatcher : IrElementVisitorVoid {
     override fun visitElement(element: IrElement) {
         element.acceptChildrenVoid(this)

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/IrElementTransformerVoidWithContext.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.backend.common
 
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.builders.Scope
@@ -101,6 +102,7 @@ abstract class IrElementTransformerVoidWithContext : IrElementTransformerVoid()
     protected val allScopes get() = scopeStack
     protected val currentDeclarationParent get() = scopeStack.lastOrNull { it.irElement is IrDeclarationParent }?.irElement as? IrDeclarationParent
 
+    @DescriptorBasedIr
     fun printScopeStack() {
         scopeStack.forEach { println(it.scope.scopeOwner) }
     }
@@ -138,6 +140,7 @@ abstract class IrElementTransformerVoidWithContext : IrElementTransformerVoid()
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 abstract class IrElementVisitorVoidWithContext : IrElementVisitorVoid {
 
     private val scopeStack = mutableListOf<ScopeWithIr>()
@@ -198,6 +201,7 @@ abstract class IrElementVisitorVoidWithContext : IrElementVisitorVoid {
     protected val parentScope get() = if (scopeStack.size < 2) null else scopeStack[scopeStack.size - 2]
     protected val allScopes get() = scopeStack
 
+    @DescriptorBasedIr
     fun printScopeStack() {
         scopeStack.forEach { println(it.scope.scopeOwner) }
     }

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/TailRecursionCallsCollector.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.backend.common
 
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrFunction
@@ -34,6 +35,7 @@ import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
  * It is also not guaranteed that each returned call is detected as tail recursion by the frontend.
  * However any returned call can be correctly optimized as tail recursion.
  */
+@OptIn(DescriptorBasedIr::class)
 fun collectTailRecursionCalls(irFunction: IrFunction): Set<IrCall> {
     if ((irFunction as? IrSimpleFunction)?.isTailrec != true) {
         return emptySet()

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/Ir.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
 import org.jetbrains.kotlin.descriptors.findClassAcrossModuleDependencies
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
 import org.jetbrains.kotlin.ir.declarations.IrPackageFragment
@@ -109,6 +110,8 @@ open class BuiltinSymbolsBase(protected val irBuiltIns: IrBuiltIns, protected va
     val intProgression = progression("IntProgression")
     val longProgression = progression("LongProgression")
     val progressionClasses = listOfNotNull(charProgression, intProgression, longProgression, uIntProgression, uLongProgression)
+
+    @DescriptorBasedIr
     val progressionClassesTypes = progressionClasses.map { it.descriptor.defaultType }.toSet()
 
     val getProgressionLastElementByReturnType = builtInsPackage("kotlin", "internal")
@@ -143,6 +146,8 @@ open class BuiltinSymbolsBase(protected val irBuiltIns: IrBuiltIns, protected va
     val long = symbolTable.referenceClass(builtIns.long)
 
     val integerClasses = listOf(byte, short, int, long)
+
+    @DescriptorBasedIr
     val integerClassesTypes = integerClasses.map { it.descriptor.defaultType }
 
     val arrayOf = getSimpleFunction(Name.identifier("arrayOf")) {

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrInlineUtils.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.backend.common.ir
 
 import org.jetbrains.kotlin.backend.common.lower.VariableRemapper
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
@@ -86,6 +87,7 @@ private fun IrBody.move(
 
 // TODO use a generic inliner (e.g. JS/Native's FunctionInlining.Inliner)
 // Inline simple function calls without type parameters, default parameters, or varargs.
+@OptIn(DescriptorBasedIr::class)
 fun IrFunction.inline(target: IrDeclarationParent, arguments: List<IrValueDeclaration> = listOf()): IrReturnableBlock =
     IrReturnableBlockImpl(startOffset, endOffset, returnType, IrReturnableBlockSymbolImpl(descriptor), null, symbol).apply {
         statements += body!!.move(this@inline, target, symbol, valueParameters.zip(arguments).toMap()).statements

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrUtils.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.Scope
@@ -130,6 +131,7 @@ fun IrCall.getAnnotationClass(): IrClass {
 
 val IrTypeParametersContainer.classIfConstructor get() = if (this is IrConstructor) parentAsClass else this
 
+@OptIn(DescriptorBasedIr::class)
 fun IrValueParameter.copyTo(
     irFunction: IrFunction,
     origin: IrDeclarationOrigin = this.origin,
@@ -172,6 +174,7 @@ fun IrValueParameter.copyTo(
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 fun IrTypeParameter.copyToWithoutSuperTypes(
     target: IrTypeParametersContainer,
     index: Int = this.index,
@@ -185,6 +188,7 @@ fun IrTypeParameter.copyToWithoutSuperTypes(
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 fun IrFunction.copyReceiverParametersFrom(from: IrFunction) {
     dispatchReceiverParameter = from.dispatchReceiverParameter?.let {
         IrValueParameterImpl(it.startOffset, it.endOffset, it.origin, it.descriptor, it.type, it.varargElementType).also {
@@ -457,6 +461,7 @@ fun IrClass.createParameterDeclarations() {
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 fun IrFunction.createDispatchReceiverParameter(origin: IrDeclarationOrigin? = null) {
     assert(dispatchReceiverParameter == null)
 
@@ -479,7 +484,7 @@ val IrFunction.allParameters: List<IrValueParameter>
     get() = if (this is IrConstructor) {
         listOf(
             this.constructedClass.thisReceiver
-                ?: error(this.descriptor)
+                ?: error(this.render())
         ) + explicitParameters
     } else {
         explicitParameters
@@ -548,6 +553,7 @@ fun IrClass.addFakeOverridesViaIncorrectHeuristic(implementedMembers: List<IrSim
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 fun createStaticFunctionWithReceivers(
     irParent: IrDeclarationParent,
     name: Name,

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/AbstractSuspendFunctionsLowering.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.backend.common.ir.*
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.declarations.*
@@ -38,6 +39,7 @@ import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.*
 import org.jetbrains.kotlin.name.Name
 
+@DescriptorBasedIr
 abstract class AbstractSuspendFunctionsLowering<C : CommonBackendContext>(val context: C) : FileLoweringPass {
 
     protected object STATEMENT_ORIGIN_COROUTINE_IMPL : IrStatementOriginImpl("COROUTINE_IMPL")

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/DefaultArgumentStubGenerator.kt

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.backend.common.ir.*
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.builders.declarations.addValueParameter
@@ -282,7 +283,11 @@ open class DefaultParameterInjector(
         expression.transformChildrenVoid()
         return visitFunctionAccessExpression(expression) {
             with(expression) {
-                IrDelegatingConstructorCallImpl(startOffset, endOffset, type, it as IrConstructorSymbol, typeArgumentsCount)
+                IrDelegatingConstructorCallImpl(
+                    startOffset, endOffset, type, it as IrConstructorSymbol,
+                    typeArgumentsCount = typeArgumentsCount,
+                    valueArgumentsCount = it.owner.valueParameters.size
+                )
             }
         }
     }
@@ -300,7 +305,11 @@ open class DefaultParameterInjector(
         expression.transformChildrenVoid()
         return visitFunctionAccessExpression(expression) {
             with(expression) {
-                IrEnumConstructorCallImpl(startOffset, endOffset, type, it as IrConstructorSymbol)
+                IrEnumConstructorCallImpl(
+                    startOffset, endOffset, type, it as IrConstructorSymbol,
+                    typeArgumentsCount = typeArgumentsCount,
+                    valueArgumentsCount = it.owner.valueParameters.size
+                )
             }
         }
     }
@@ -309,7 +318,13 @@ open class DefaultParameterInjector(
         expression.transformChildrenVoid()
         return visitFunctionAccessExpression(expression) {
             with(expression) {
-                IrCallImpl(startOffset, endOffset, type, it, typeArgumentsCount, DEFAULT_DISPATCH_CALL, superQualifierSymbol)
+                IrCallImpl(
+                    startOffset, endOffset, type, it,
+                    typeArgumentsCount = typeArgumentsCount,
+                    valueArgumentsCount = it.owner.valueParameters.size,
+                    origin = DEFAULT_DISPATCH_CALL,
+                    superQualifierSymbol = superQualifierSymbol
+                )
             }
         }
     }
@@ -480,6 +495,7 @@ private fun IrFunction.generateDefaultsFunction(
     return null
 }
 
+@OptIn(DescriptorBasedIr::class)
 private fun IrFunction.generateDefaultsFunctionImpl(
     context: CommonBackendContext,
     newOrigin: IrDeclarationOrigin,

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/EnumWhenLowering.kt

@@ -102,7 +102,12 @@ open class EnumWhenLowering(protected val context: CommonBackendContext) : IrEle
             else -> return super.visitCall(expression)
         }
         val subjectOrdinal = topmostOrdinalProvider.value
-        return IrCallImpl(expression.startOffset, expression.endOffset, expression.type, expression.symbol).apply {
+        return IrCallImpl(
+            expression.startOffset, expression.endOffset,
+            expression.type, expression.symbol,
+            typeArgumentsCount = 0,
+            valueArgumentsCount = 2
+        ).apply {
             putValueArgument(0, IrGetValueImpl(lhs.startOffset, lhs.endOffset, subjectOrdinal.type, subjectOrdinal.symbol))
             putValueArgument(1, IrConstImpl.int(rhs.startOffset, rhs.endOffset, context.irBuiltIns.intType, entryOrdinal))
         }

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/InnerClassesLowering.kt

@@ -17,13 +17,11 @@ 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.classOrNull
-import org.jetbrains.kotlin.ir.util.deepCopyWithSymbols
 import org.jetbrains.kotlin.ir.util.dump
 import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.ir.util.patchDeclarationParents
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
-import org.jetbrains.kotlin.utils.addToStdlib.cast
 
 class InnerClassesLowering(val context: BackendContext) : DeclarationTransformer {
 
@@ -225,7 +223,9 @@ class InnerClassConstructorCallsLowering(val context: BackendContext) : BodyLowe
 
                 val newCallee = context.declarationFactory.getInnerClassConstructorWithOuterThisParameter(classConstructor)
                 val newCall = IrDelegatingConstructorCallImpl(
-                    expression.startOffset, expression.endOffset, context.irBuiltIns.unitType, newCallee.symbol, expression.typeArgumentsCount
+                    expression.startOffset, expression.endOffset, context.irBuiltIns.unitType, newCallee.symbol,
+                    typeArgumentsCount = expression.typeArgumentsCount,
+                    valueArgumentsCount = newCallee.valueParameters.size
                 ).apply { copyTypeArgumentsFrom(expression) }
 
                 newCall.putValueArgument(0, dispatchReceiver)
@@ -258,9 +258,10 @@ class InnerClassConstructorCallsLowering(val context: BackendContext) : BodyLowe
                         endOffset,
                         type,
                         newCallee.symbol,
-                        typeArgumentsCount,
+                        typeArgumentsCount = typeArgumentsCount,
-                        newReflectionTarget?.symbol,
+                        valueArgumentsCount = newCallee.valueParameters.size,
-                        origin
+                        reflectionTarget = newReflectionTarget?.symbol,
+                        origin = origin
                     )
                 }
 

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LocalDeclarationsLowering.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.ReceiverParameterDescriptor
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
@@ -47,7 +48,6 @@ import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 import java.util.*
 
 interface LocalNameProvider {
@@ -229,6 +229,7 @@ class LocalDeclarationsLowering(
             abbreviation.annotations
         )
 
+    @OptIn(DescriptorBasedIr::class)
     private inner class LocalDeclarationsTransformer(
         val irElement: IrElement, val container: IrDeclaration, val classesToLower: Set<IrClass>?
     ) {
@@ -358,7 +359,8 @@ class LocalDeclarationsLowering(
                     expression.startOffset, expression.endOffset,
                     context.irBuiltIns.unitType,
                     newCallee.symbol,
-                    expression.typeArgumentsCount
+                    typeArgumentsCount = expression.typeArgumentsCount,
+                    valueArgumentsCount = newCallee.valueParameters.size
                 ).also {
                     it.fillArguments2(expression, newCallee)
                     it.copyTypeArgumentsFrom(expression)
@@ -416,9 +418,10 @@ class LocalDeclarationsLowering(
                     expression.startOffset, expression.endOffset,
                     expression.type, // TODO functional type for transformed descriptor
                     newCallee.symbol,
-                    newCallee.typeParameters.size,
+                    typeArgumentsCount = newCallee.typeParameters.size,
-                    newReflectionTarget?.symbol,
+                    valueArgumentsCount = newCallee.valueParameters.size,
-                    expression.origin
+                    reflectionTarget = newReflectionTarget?.symbol,
+                    origin = expression.origin
                 ).also {
                     it.fillArguments2(expression, newCallee)
                     it.setLocalTypeArguments(oldCallee)
@@ -519,9 +522,10 @@ class LocalDeclarationsLowering(
                 oldCall.startOffset, oldCall.endOffset,
                 newCallee.returnType,
                 newCallee.symbol,
-                newCallee.typeParameters.size,
+                typeArgumentsCount = newCallee.typeParameters.size,
-                oldCall.origin,
+                valueArgumentsCount = newCallee.valueParameters.size,
-                oldCall.superQualifierSymbol
+                origin = oldCall.origin,
+                superQualifierSymbol = oldCall.superQualifierSymbol
             ).also {
                 it.setLocalTypeArguments(oldCall.symbol.owner)
                 it.copyTypeArgumentsFrom(oldCall, shift = newCallee.typeParameters.size - oldCall.typeArgumentsCount)

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/LowerUtils.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.backend.common.lower
 import org.jetbrains.kotlin.backend.common.BackendContext
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.impl.ValueParameterDescriptorImpl
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
@@ -63,6 +64,7 @@ open class VariableRemapper(val mapping: Map<IrValueParameter, IrValueDeclaratio
         mapping[value]
 }
 
+@DescriptorBasedIr
 class VariableRemapperDesc(val mapping: Map<ValueDescriptor, IrValueParameter>) : AbstractVariableRemapper() {
     override fun remapVariable(value: IrValueDeclaration): IrValueDeclaration? =
         mapping[value.descriptor]
@@ -158,6 +160,7 @@ open class IrBuildingTransformer(private val context: BackendContext) : IrElemen
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 fun IrConstructor.callsSuper(irBuiltIns: IrBuiltIns): Boolean {
     val constructedClass = parent as IrClass
     val superClass = constructedClass.superTypes

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/ProvisionalFunctionExpressionLowering.kt

@@ -42,6 +42,7 @@ class ProvisionalFunctionExpressionLowering :
                     startOffset, endOffset, type,
                     function.symbol,
                     typeArgumentsCount = 0,
+                    valueArgumentsCount = function.valueParameters.size,
                     reflectionTarget = null,
                     origin = origin
                 )

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/inline/FunctionInlining.kt

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.backend.common.ir.Symbols
 import org.jetbrains.kotlin.backend.common.ir.createTemporaryVariableWithWrappedDescriptor
 import org.jetbrains.kotlin.backend.common.lower.createIrBuilder
 import org.jetbrains.kotlin.config.languageVersionSettings
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
@@ -36,6 +37,7 @@ interface InlineFunctionResolver {
     fun getFunctionDeclaration(symbol: IrFunctionSymbol): IrFunction
 }
 
+@OptIn(DescriptorBasedIr::class)
 open class DefaultInlineFunctionResolver(open val context: CommonBackendContext) : InlineFunctionResolver {
     override fun getFunctionDeclaration(symbol: IrFunctionSymbol): IrFunction {
         val descriptor = symbol.descriptor.original
@@ -56,6 +58,7 @@ open class DefaultInlineFunctionResolver(open val context: CommonBackendContext)
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 class FunctionInlining(
     val context: CommonBackendContext,
     val inlineFunctionResolver: InlineFunctionResolver
@@ -164,10 +167,6 @@ class FunctionInlining(
             statements.transform { it.transform(transformer, data = null) }
             statements.addAll(0, evaluationStatements)
 
-            val isCoroutineIntrinsicCall = callSite.symbol.descriptor.isBuiltInSuspendCoroutineUninterceptedOrReturn(
-                context.configuration.languageVersionSettings
-            )
-
             return IrReturnableBlockImpl(
                 startOffset = callSite.startOffset,
                 endOffset = callSite.endOffset,
@@ -414,7 +413,7 @@ class FunctionInlining(
                     }
 
                     else -> {
-                        val message = "Incomplete expression: call to ${callee.descriptor} " +
+                        val message = "Incomplete expression: call to ${callee.render()} " +
                                 "has no argument at index ${parameter.index}"
                         throw Error(message)
                     }

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/loops/ProgressionHandlers.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.backend.common.lower.matchers.Quantifier
 import org.jetbrains.kotlin.backend.common.lower.matchers.SimpleCalleeMatcher
 import org.jetbrains.kotlin.backend.common.lower.matchers.createIrCallMatcher
 import org.jetbrains.kotlin.backend.common.lower.matchers.singleArgumentExtension
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
 import org.jetbrains.kotlin.ir.declarations.IrVariable
@@ -555,6 +556,7 @@ internal class CharSequenceIndicesHandler(context: CommonBackendContext) : Indic
 }
 
 /** Builds a [HeaderInfo] for calls to reverse an iterable. */
+@OptIn(DescriptorBasedIr::class)
 internal class ReversedHandler(context: CommonBackendContext, private val visitor: HeaderInfoBuilder) :
     HeaderInfoFromCallHandler<Nothing?> {
 

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/loops/ProgressionType.kt

@@ -10,6 +10,7 @@ package org.jetbrains.kotlin.backend.common.lower.loops
 import org.jetbrains.kotlin.backend.common.CommonBackendContext
 import org.jetbrains.kotlin.backend.common.ir.Symbols
 import org.jetbrains.kotlin.backend.common.lower.DeclarationIrBuilder
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.builders.irChar
 import org.jetbrains.kotlin.ir.builders.irInt
 import org.jetbrains.kotlin.ir.builders.irLong
@@ -48,8 +49,12 @@ internal sealed class ProgressionType(
                 it.name == numberCastFunctionName &&
                         it.dispatchReceiverParameter != null && it.extensionReceiverParameter == null && it.valueParameters.isEmpty()
             }
-            IrCallImpl(startOffset, endOffset, castFun.returnType, castFun.symbol)
+            IrCallImpl(
-                .apply { dispatchReceiver = this@castIfNecessary }
+                startOffset, endOffset,
+                castFun.returnType, castFun.symbol,
+                typeArgumentsCount = 0,
+                valueArgumentsCount = 0
+            ).apply { dispatchReceiver = this@castIfNecessary }
         }
 
     companion object {
@@ -139,14 +144,25 @@ internal abstract class UnsignedProgressionType(
         if (type == unsignedType) return this
 
         return if (unsafeCoerceIntrinsic != null) {
-            IrCallImpl(startOffset, endOffset, unsignedType, unsafeCoerceIntrinsic).apply {
+            IrCallImpl(
+                startOffset, endOffset,
+                unsignedType,
+                unsafeCoerceIntrinsic,
+                typeArgumentsCount = 2,
+                valueArgumentsCount = 1
+            ).apply {
                 putTypeArgument(0, fromType)
                 putTypeArgument(1, unsignedType)
                 putValueArgument(0, this@asUnsigned)
             }
         } else {
             // Fallback to calling `toUInt/ULong()` extension function.
-            IrCallImpl(startOffset, endOffset, unsignedConversionFunction.owner.returnType, unsignedConversionFunction).apply {
+            IrCallImpl(
+                startOffset, endOffset, unsignedConversionFunction.owner.returnType,
+                unsignedConversionFunction,
+                typeArgumentsCount = 0,
+                valueArgumentsCount = 0
+            ).apply {
                 extensionReceiver = this@asUnsigned
             }
         }
@@ -157,7 +173,12 @@ internal abstract class UnsignedProgressionType(
         if (type == toType) return this
 
         return if (unsafeCoerceIntrinsic != null) {
-            IrCallImpl(startOffset, endOffset, toType, unsafeCoerceIntrinsic).apply {
+            IrCallImpl(
+                startOffset, endOffset, toType,
+                unsafeCoerceIntrinsic,
+                typeArgumentsCount = 2,
+                valueArgumentsCount = 1
+            ).apply {
                 putTypeArgument(0, unsignedType)
                 putTypeArgument(1, toType)
                 putValueArgument(0, this@asSigned)
@@ -169,6 +190,7 @@ internal abstract class UnsignedProgressionType(
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 internal class UIntProgressionType(symbols: Symbols<CommonBackendContext>) :
     UnsignedProgressionType(
         symbols,
@@ -186,6 +208,7 @@ internal class UIntProgressionType(symbols: Symbols<CommonBackendContext>) :
     override fun DeclarationIrBuilder.zeroStepExpression() = irInt(0)
 }
 
+@OptIn(DescriptorBasedIr::class)
 internal class ULongProgressionType(symbols: Symbols<CommonBackendContext>) :
     UnsignedProgressionType(
         symbols,

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/loops/Utils.kt

@@ -8,7 +8,6 @@ package org.jetbrains.kotlin.backend.common.lower.loops
 import org.jetbrains.kotlin.backend.common.lower.DeclarationIrBuilder
 import org.jetbrains.kotlin.ir.builders.createTmpVariable
 import org.jetbrains.kotlin.ir.builders.irGet
-import org.jetbrains.kotlin.ir.declarations.IrValueDeclaration
 import org.jetbrains.kotlin.ir.declarations.IrVariable
 import org.jetbrains.kotlin.ir.expressions.IrConst
 import org.jetbrains.kotlin.ir.expressions.IrConstKind
@@ -16,7 +15,6 @@ import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrGetValue
 import org.jetbrains.kotlin.ir.expressions.impl.IrCallImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrConstImpl
-import org.jetbrains.kotlin.ir.symbols.IrVariableSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.types.getClass
 import org.jetbrains.kotlin.ir.types.isNothing
@@ -36,7 +34,12 @@ internal fun IrExpression.negate(): IrExpression {
                 it.name == OperatorNameConventions.UNARY_MINUS &&
                         it.valueParameters.isEmpty()
             }
-            IrCallImpl(startOffset, endOffset, type, unaryMinusFun.symbol).apply {
+            IrCallImpl(
+                startOffset, endOffset, type,
+                unaryMinusFun.symbol,
+                valueArgumentsCount = 0,
+                typeArgumentsCount = 0
+            ).apply {
                 dispatchReceiver = this@negate
             }
         }
@@ -54,7 +57,12 @@ internal fun IrExpression.decrement(): IrExpression {
                 it.name == OperatorNameConventions.DEC &&
                         it.valueParameters.isEmpty()
             }
-            IrCallImpl(startOffset, endOffset, type, decFun.symbol).apply {
+            IrCallImpl(
+                startOffset, endOffset, type,
+                decFun.symbol,
+                valueArgumentsCount = 0,
+                typeArgumentsCount = 0
+            ).apply {
                 dispatchReceiver = this@decrement
             }
         }

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/matchers/IrFunctionMatcher.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.backend.common.lower.matchers
 
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.IrValueParameter
 import org.jetbrains.kotlin.ir.types.IrType
@@ -51,6 +52,7 @@ internal class ParameterCountMatcher(
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 internal class FqNameMatcher(
     val restriction: (FqName) -> Boolean
 ) : IrFunctionMatcher {

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsDeclarationFactory.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.backend.common.ir.copyTypeParametersFrom
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.backend.js.JsMapping
 import org.jetbrains.kotlin.ir.backend.js.ir.JsIrBuilder
@@ -94,6 +95,7 @@ class JsDeclarationFactory(mapping: JsMapping) : DeclarationFactory {
         return originalInnerClassPrimaryConstructorByClass[innerClass]
     }
 
+    @OptIn(DescriptorBasedIr::class)
     private fun createInnerClassConstructorWithOuterThisParameter(oldConstructor: IrConstructor): IrConstructor {
         val irClass = oldConstructor.parent as IrClass
         val outerThisType = (irClass.parent as IrClass).defaultType

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt

@@ -14,10 +14,7 @@ import org.jetbrains.kotlin.config.CompilerConfiguration
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.impl.EmptyPackageFragmentDescriptor
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
-import org.jetbrains.kotlin.ir.IrElement
+import org.jetbrains.kotlin.ir.*
-import org.jetbrains.kotlin.ir.SourceManager
-import org.jetbrains.kotlin.ir.SourceRangeInfo
-import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.backend.js.ir.JsIrBuilder
 import org.jetbrains.kotlin.ir.backend.js.utils.OperatorNames
 import org.jetbrains.kotlin.ir.declarations.*
@@ -60,6 +57,8 @@ class JsIrBackendContext(
 
     val externalPackageFragment = mutableMapOf<IrFileSymbol, IrFile>()
     val externalDeclarations = hashSetOf<IrDeclaration>()
+
+    @OptIn(DescriptorBasedIr::class)
     val bodilessBuiltInsPackageFragment: IrPackageFragment = run {
 
         class DescriptorlessExternalPackageFragmentSymbol : IrExternalPackageFragmentSymbol {

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsSharedVariablesManager.kt

@@ -45,10 +45,15 @@ class JsSharedVariablesManager(val builtIns: IrBuiltIns, val implicitDeclaration
         val constructorSymbol = closureBoxConstructorDeclaration.symbol
 
         val irCall =
-            IrConstructorCallImpl.fromSymbolDescriptor(initializer.startOffset, initializer.endOffset, closureBoxType, constructorSymbol)
+            IrConstructorCallImpl(
-                .apply {
+                initializer.startOffset, initializer.endOffset,
-                    putValueArgument(0, initializer)
+                closureBoxType, constructorSymbol,
-                }
+                valueArgumentsCount = 1,
+                typeArgumentsCount = 0,
+                constructorTypeArgumentsCount = 0
+            ).apply {
+                putValueArgument(0, initializer)
+            }
 
         val descriptor = WrappedVariableDescriptor()
         return IrVariableImpl(

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/ir/IrBuilder.kt

@@ -26,20 +26,23 @@ object JsIrBuilder {
     object SYNTHESIZED_STATEMENT : IrStatementOriginImpl("SYNTHESIZED_STATEMENT")
     object SYNTHESIZED_DECLARATION : IrDeclarationOriginImpl("SYNTHESIZED_DECLARATION")
 
-    fun buildCall(target: IrFunctionSymbol, type: IrType? = null, typeArguments: List<IrType>? = null): IrCall =
+    fun buildCall(target: IrFunctionSymbol, type: IrType? = null, typeArguments: List<IrType>? = null): IrCall {
-        IrCallImpl(
+        val owner = target.owner
+        return IrCallImpl(
             UNDEFINED_OFFSET,
             UNDEFINED_OFFSET,
-            type ?: target.owner.returnType,
+            type ?: owner.returnType,
             target,
-            target.owner.typeParameters.size,
+            typeArgumentsCount = owner.typeParameters.size,
-            SYNTHESIZED_STATEMENT
+            valueArgumentsCount = owner.valueParameters.size,
+            origin = SYNTHESIZED_STATEMENT
         ).apply {
             typeArguments?.let {
                 assert(typeArguments.size == typeArgumentsCount)
                 it.withIndex().forEach { (i, t) -> putTypeArgument(i, t) }
             }
         }
+    }
 
     fun buildReturn(targetSymbol: IrFunctionSymbol, value: IrExpression, type: IrType) =
         IrReturnImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, type, targetSymbol, value)
@@ -191,9 +194,6 @@ object JsIrBuilder {
     fun buildComposite(type: IrType, statements: List<IrStatement> = emptyList()) =
         IrCompositeImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, type, SYNTHESIZED_STATEMENT, statements)
 
-    fun buildFunctionReference(type: IrType, symbol: IrFunctionSymbol, reflectionTarget: IrFunctionSymbol? = symbol) =
-        IrFunctionReferenceImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, type, symbol, 0, reflectionTarget, null)
-
     fun buildFunctionExpression(type: IrType, function: IrSimpleFunction) =
         IrFunctionExpressionImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, type, function, SYNTHESIZED_STATEMENT)
 

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/BridgesConstruction.kt

@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.backend.common.ir.isMethodOfAny
 import org.jetbrains.kotlin.backend.common.ir.isSuspend
 import org.jetbrains.kotlin.backend.common.lower.*
 import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.backend.js.JsLoweredDeclarationOrigin
 import org.jetbrains.kotlin.ir.backend.js.ir.JsIrBuilder
@@ -48,6 +49,7 @@ import org.jetbrains.kotlin.ir.util.*
 //            fun foo(t: Any?) = foo(t as Int)  // Constructed bridge
 //          }
 //
+@OptIn(DescriptorBasedIr::class)
 class BridgesConstruction(val context: CommonBackendContext) : DeclarationTransformer {
 
     private val specialBridgeMethods = SpecialBridgeMethods(context)

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/CreateScriptFunctionsPhase.kt

@@ -131,6 +131,11 @@ class CreateScriptFunctionsPhase(val context: CommonBackendContext) : FileLoweri
     }
 
     private fun createCall(function: IrFunction): IrCall {
-        return IrCallImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, function.returnType, function.symbol)
+        return IrCallImpl(
+            UNDEFINED_OFFSET, UNDEFINED_OFFSET, function.returnType,
+            function.symbol,
+            valueArgumentsCount = function.valueParameters.size,
+            typeArgumentsCount = function.typeParameters.size
+        )
     }
 }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/EnumClassLowering.kt

@@ -528,7 +528,12 @@ class EnumSyntheticFunctionsLowering(val context: JsIrBackendContext): Declarati
     private fun List<IrExpression>.toArrayLiteral(arrayType: IrType, elementType: IrType): IrExpression {
         val irVararg = IrVarargImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, arrayType, elementType, this)
 
-        return IrCallImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, arrayType, context.intrinsics.arrayLiteral).apply {
+        return IrCallImpl(
+            UNDEFINED_OFFSET, UNDEFINED_OFFSET, arrayType,
+            context.intrinsics.arrayLiteral,
+            typeArgumentsCount = 0,
+            valueArgumentsCount = 1
+        ).apply {
             putValueArgument(0, irVararg)
         }
     }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/JsDefaultArgumentStubGenerator.kt

@@ -80,6 +80,7 @@ class JsDefaultCallbackGenerator(val context: JsIrBackendContext): BodyLoweringP
                 context.irBuiltIns.anyType,
                 originalFunction.symbol,
                 typeArgumentsCount = 0,
+                valueArgumentsCount = originalFunction.valueParameters.size,
                 reflectionTarget = originalFunction.symbol,
                 origin = BIND_CALL
             )
@@ -91,8 +92,10 @@ class JsDefaultCallbackGenerator(val context: JsIrBackendContext): BodyLoweringP
                 endOffset,
                 context.irBuiltIns.anyType,
                 context.intrinsics.jsBind.symbol,
-                BIND_CALL,
+                valueArgumentsCount = 2,
-                superQualifierSymbol
+                typeArgumentsCount = 0,
+                origin = BIND_CALL,
+                superQualifierSymbol = superQualifierSymbol
             )
         }.apply {
             putValueArgument(0, irCall.dispatchReceiver?.deepCopyWithSymbols())

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/MoveBodilessDeclarationsToSeparatePlace.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.ir.backend.js.lower
 import org.jetbrains.kotlin.backend.common.DeclarationTransformer
 import org.jetbrains.kotlin.backend.common.ir.addChild
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.backend.js.JsIrBackendContext
 import org.jetbrains.kotlin.ir.backend.js.utils.getJsModule
@@ -49,6 +50,7 @@ private class DescriptorlessIrFileSymbol : IrFileSymbol {
         _owner = owner
     }
 
+    @DescriptorBasedIr
     override val descriptor: PackageFragmentDescriptor
         get() = error("Operation is unsupported")
 

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/PrimaryConstructorLowering.kt

@@ -71,7 +71,12 @@ class DelegateToSyntheticPrimaryConstructor(context: JsCommonBackendContext) : B
                     override fun visitDeclaration(declaration: IrDeclaration) = declaration // optimize visiting
 
                     override fun visitInstanceInitializerCall(expression: IrInstanceInitializerCall) = expression.run {
-                        IrDelegatingConstructorCallImpl(startOffset, endOffset, type, primary.symbol)
+                        IrDelegatingConstructorCallImpl(
+                            startOffset, endOffset, type,
+                            primary.symbol,
+                            valueArgumentsCount = primary.valueParameters.size,
+                            typeArgumentsCount = primary.typeParameters.size
+                        )
                     }
                 }
 

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/PrivateMembersLowering.kt

@@ -199,9 +199,11 @@ class PrivateMemberBodiesLowering(val context: JsIrBackendContext) : BodyLowerin
                 val newExpression = IrCallImpl(
                     expression.startOffset, expression.endOffset,
                     expression.type,
-                    staticTarget.symbol, expression.typeArgumentsCount,
+                    staticTarget.symbol,
-                    expression.origin,
+                    typeArgumentsCount = expression.typeArgumentsCount,
-                    expression.superQualifierSymbol
+                    valueArgumentsCount = expression.valueArgumentsCount + 1,
+                    origin = expression.origin,
+                    superQualifierSymbol = expression.superQualifierSymbol
                 )
 
                 newExpression.extensionReceiver = expression.extensionReceiver

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ScriptRemoveReceiverLowering.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.ir.backend.js.lower
 import org.jetbrains.kotlin.backend.common.CommonBackendContext
 import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.descriptors.ScriptDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.IrConstImpl
@@ -36,6 +37,7 @@ class ScriptRemoveReceiverLowering(val context: CommonBackendContext) : FileLowe
 
     private fun IrExpression.nullConst() = IrConstImpl.constNull(startOffset, endOffset, type.makeNullable())
 
+    @OptIn(DescriptorBasedIr::class)
     fun lower(script: IrScript): List<IrScript> {
         val transformer: IrElementTransformerVoid = object : IrElementTransformerVoid() {
             override fun visitCall(expression: IrCall): IrExpression {

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/SecondaryCtorLowering.kt

@@ -272,7 +272,11 @@ private class CallsiteRedirectionTransformer(private val context: JsIrBackendCon
     private fun replaceSecondaryConstructorWithFactoryFunction(
         call: IrFunctionAccessExpression,
         newTarget: IrSimpleFunctionSymbol
-    ) = IrCallImpl(call.startOffset, call.endOffset, call.type, newTarget, call.typeArgumentsCount).apply {
+    ) = IrCallImpl(
+        call.startOffset, call.endOffset, call.type, newTarget,
+        typeArgumentsCount = call.typeArgumentsCount,
+        valueArgumentsCount = newTarget.owner.valueParameters.size
+    ).apply {
 
         copyTypeArgumentsFrom(call)
 

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ThrowableLowering.kt

@@ -72,7 +72,11 @@ class ThrowableLowering(
             val (messageArg, causeArg) = expression.extractThrowableArguments()
 
             return expression.run {
-                IrCallImpl(startOffset, endOffset, type, newThrowableFunction).also {
+                IrCallImpl(
+                    startOffset, endOffset, type, newThrowableFunction,
+                    valueArgumentsCount = 2,
+                    typeArgumentsCount = 0
+                ).also {
                     it.putValueArgument(0, messageArg)
                     it.putValueArgument(1, causeArg)
                 }
@@ -89,7 +93,11 @@ class ThrowableLowering(
             val thisReceiver = IrGetValueImpl(expression.startOffset, expression.endOffset, klass.thisReceiver!!.symbol)
 
             return expression.run {
-                IrCallImpl(startOffset, endOffset, type, extendThrowableFunction).also {
+                IrCallImpl(
+                    startOffset, endOffset, type, extendThrowableFunction,
+                    valueArgumentsCount = 3,
+                    typeArgumentsCount = 0
+                ).also {
                     it.putValueArgument(0, thisReceiver)
                     it.putValueArgument(1, messageArg)
                     it.putValueArgument(2, causeArg)

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/VarargLowering.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.backend.js.lower
 
 import org.jetbrains.kotlin.backend.common.BodyLoweringPass
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.backend.js.JsIrBackendContext
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
@@ -30,6 +31,7 @@ private class VarargTransformer(
     val context: JsIrBackendContext
 ) : IrElementTransformerVoid() {
 
+    @OptIn(DescriptorBasedIr::class)
     private fun List<IrExpression>.toArrayLiteral(type: IrType, varargElementType: IrType): IrExpression {
 
         // TODO: Use symbols when builtins symbol table is fixes
@@ -47,8 +49,15 @@ private class VarargTransformer(
 
         val irVararg = IrVarargImpl(startOffset, endOffset, type, varargElementType, this)
 
-        return IrCallImpl(startOffset, endOffset, type, intrinsic).apply {
+        return IrCallImpl(
-            if (intrinsic.owner.typeParameters.isNotEmpty()) putTypeArgument(0, varargElementType)
+            startOffset, endOffset,
+            type, intrinsic,
+            typeArgumentsCount = if (intrinsic.owner.typeParameters.isNotEmpty()) 1 else 0,
+            valueArgumentsCount = 1
+        ).apply {
+            if (typeArgumentsCount == 1) {
+                putTypeArgument(0, varargElementType)
+            }
             putValueArgument(0, irVararg)
         }
     }
@@ -149,7 +158,9 @@ private class VarargTransformer(
                     expression.startOffset,
                     expression.endOffset,
                     arrayInfo.primitiveArrayType,
-                    copyFunction
+                    copyFunction,
+                    typeArgumentsCount = 1,
+                    valueArgumentsCount = 1
                 ).apply {
                     putTypeArgument(0, arrayInfo.primitiveArrayType)
                     putValueArgument(0, segment)
@@ -175,7 +186,9 @@ private class VarargTransformer(
             expression.startOffset,
             expression.endOffset,
             arrayInfo.primitiveArrayType,
-            concatFun
+            concatFun,
+            typeArgumentsCount = 0,
+            valueArgumentsCount = 1
         ).apply {
             putValueArgument(0, arrayLiteral)
         }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/calls/EqualityAndComparisonCallsTransformer.kt

@@ -51,7 +51,9 @@ class EqualityAndComparisonCallsTransformer(context: JsIrBackendContext) : Calls
             call.startOffset,
             call.endOffset,
             comparator.owner.returnType,
-            comparator
+            comparator,
+            typeArgumentsCount = 0,
+            valueArgumentsCount = 2
         ).apply {
             putValueArgument(0, irCall(call, intrinsics.longCompareToLong, argumentsAsReceivers = true))
             putValueArgument(1, JsIrBuilder.buildInt(irBuiltIns.intType, 0))

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/calls/NumberOperatorCallsTransformer.kt

@@ -208,7 +208,9 @@ class NumberOperatorCallsTransformer(context: JsIrBackendContext) : CallsTransfo
                             call.startOffset,
                             call.endOffset,
                             intrinsics.longToDouble.owner.returnType,
-                            intrinsics.longToDouble
+                            intrinsics.longToDouble,
+                            typeArgumentsCount = 0,
+                            valueArgumentsCount = 0
                         ).apply {
                             dispatchReceiver = arg
                         })
@@ -219,7 +221,9 @@ class NumberOperatorCallsTransformer(context: JsIrBackendContext) : CallsTransfo
                             call.startOffset,
                             call.endOffset,
                             intrinsics.longToFloat.owner.returnType,
-                            intrinsics.longToFloat
+                            intrinsics.longToFloat,
+                            typeArgumentsCount = 0,
+                            valueArgumentsCount = 0
                         ).apply {
                             dispatchReceiver = arg
                         })
@@ -230,7 +234,9 @@ class NumberOperatorCallsTransformer(context: JsIrBackendContext) : CallsTransfo
                             call.startOffset,
                             call.endOffset,
                             intrinsics.jsNumberToLong.owner.returnType,
-                            intrinsics.jsNumberToLong
+                            intrinsics.jsNumberToLong,
+                            typeArgumentsCount = 0,
+                            valueArgumentsCount = 1
                         ).apply {
                             putValueArgument(0, call.dispatchReceiver)
                         }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/calls/PrimitiveContainerMemberCallTransformer.kt

@@ -38,7 +38,9 @@ class PrimitiveContainerMemberCallTransformer(private val context: JsIrBackendCo
                         call.startOffset,
                         call.endOffset,
                         call.type,
-                        context.intrinsics.primitiveToSizeConstructor[elementType]!!
+                        context.intrinsics.primitiveToSizeConstructor[elementType]!!,
+                        typeArgumentsCount = 0,
+                        valueArgumentsCount = 1
                     ).apply {
                         putValueArgument(0, call.getValueArgument(0))
                     }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/misc.kt

@@ -6,7 +6,6 @@
 package org.jetbrains.kotlin.ir.backend.js.utils
 
 import org.jetbrains.kotlin.ir.IrElement
-import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.backend.js.JsIrBackendContext
 import org.jetbrains.kotlin.ir.declarations.*
@@ -37,7 +36,12 @@ fun IrDeclaration.hasStaticDispatch() = when (this) {
 fun List<IrExpression>.toJsArrayLiteral(context: JsIrBackendContext, arrayType: IrType, elementType: IrType): IrExpression {
     val irVararg = IrVarargImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, arrayType, elementType, this)
 
-    return IrCallImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, arrayType, context.intrinsics.arrayLiteral).apply {
+    return IrCallImpl(
+        UNDEFINED_OFFSET, UNDEFINED_OFFSET, arrayType,
+        context.intrinsics.arrayLiteral,
+        valueArgumentsCount = 1,
+        typeArgumentsCount = 0
+    ).apply {
         putValueArgument(0, irVararg)
     }
 }

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/AddContinuationLowering.kt

@@ -276,7 +276,7 @@ private class AddContinuationLowering(private val context: JvmBackendContext) :
     // TODO: fix the generic signature -- type parameters of FunctionN should be substituted
     private fun IrClass.addInvokeCallingCreate(
         create: IrFunction,
-        invokeSuspend: IrFunction,
+        invokeSuspend: IrSimpleFunction,
         invokeToOverride: IrSimpleFunctionSymbol
     ) = addFunctionOverride(invokeToOverride.owner) { function ->
         val newlyCreatedObject = irCall(create).also { createCall ->
@@ -292,7 +292,7 @@ private class AddContinuationLowering(private val context: JvmBackendContext) :
     // versions; for other lambdas, there's no point in generating a non-overriding `create` separately.
     private fun IrClass.addInvokeCallingConstructor(
         constructor: IrFunction,
-        invokeSuspend: IrFunction,
+        invokeSuspend: IrSimpleFunction,
         invokeToOverride: IrSimpleFunctionSymbol,
         fieldsForBound: List<IrField>,
         fieldsForUnbound: List<IrField>
@@ -334,7 +334,7 @@ private class AddContinuationLowering(private val context: JvmBackendContext) :
         return irGet(result)
     }
 
-    private fun IrBlockBodyBuilder.callInvokeSuspend(invokeSuspend: IrFunction, lambda: IrExpression): IrExpression {
+    private fun IrBlockBodyBuilder.callInvokeSuspend(invokeSuspend: IrSimpleFunction, lambda: IrExpression): IrExpression {
         // SingletonReferencesLowering has finished a while ago, so `irUnit()` won't work anymore.
         val unitClass = context.irBuiltIns.unitClass
         val unitField = this@AddContinuationLowering.context.declarationFactory.getFieldForObjectInstance(unitClass.owner)

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmBackendContext.kt

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.backend.js.JsDeclarationFactory
 import org.jetbrains.kotlin.config.CompilerConfiguration
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.backend.js.JsCommonBackendContext
 import org.jetbrains.kotlin.ir.backend.js.JsMapping
@@ -80,6 +81,7 @@ class WasmBackendContext(
 }
 
 class DescriptorlessExternalPackageFragmentSymbol : IrExternalPackageFragmentSymbol {
+    @DescriptorBasedIr
     override val descriptor: PackageFragmentDescriptor
         get() = error("Operation is unsupported")
 

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ClassGenerator.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.psi2ir.generators
 import org.jetbrains.kotlin.backend.common.CodegenUtil
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.IrClassImpl
 import org.jetbrains.kotlin.ir.descriptors.IrImplementingDelegateDescriptorImpl
@@ -55,6 +56,7 @@ import org.jetbrains.kotlin.types.TypeProjectionImpl
 import org.jetbrains.kotlin.types.TypeSubstitutor
 import org.jetbrains.kotlin.utils.newHashMapWithExpectedSize
 
+@OptIn(DescriptorBasedIr::class)
 class ClassGenerator(
     declarationGenerator: DeclarationGenerator
 ) : DeclarationGeneratorExtension(declarationGenerator) {

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/DeclarationGenerator.kt

@@ -174,7 +174,7 @@ abstract class DeclarationGeneratorExtension(val declarationGenerator: Declarati
 
     inline fun <T : IrDeclaration> T.buildWithScope(builder: (T) -> Unit): T =
         also { irDeclaration ->
-            context.symbolTable.withScope(irDeclaration.descriptor) {
+            context.symbolTable.withScope(irDeclaration) {
                 builder(irDeclaration)
             }
         }

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/IrSyntheticDeclarationGenerator.kt

@@ -39,7 +39,7 @@ class IrSyntheticDeclarationGenerator(context: GeneratorContext) : IrElementVisi
 
         contributedDescriptors.removeAll(declaredDescriptors)
 
-        symbolTable.withScope(irClass.descriptor) {
+        symbolTable.withScope(irClass) {
             contributedDescriptors.forEach { it.accept(descriptorGenerator, irClass) }
         }
     }

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/OperatorExpressionGenerator.kt

@@ -499,7 +499,7 @@ class OperatorExpressionGenerator(statementGenerator: StatementGenerator) : Stat
             ?: throw AssertionError("No type for !! argument")
         val expressionType = argumentType.makeNotNullable()
 
-        val checkNotNull = context.irBuiltIns.checkNotNull
+        val checkNotNull = context.irBuiltIns.checkNotNullSymbol.descriptor
         val checkNotNullSubstituted =
             checkNotNull.substitute(
                 TypeSubstitutor.create(

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/StandaloneDeclarationGenerator.kt

@@ -78,7 +78,7 @@ class StandaloneDeclarationGenerator(private val context: GeneratorContext) {
 
         val irClass = IrClassImpl(startOffset, endOffset, origin, symbol, descriptor)
 
-        symbolTable.withScope(descriptor) {
+        symbolTable.withScope(irClass) {
             irClass.metadata = MetadataSource.Class(descriptor)
 
             generateGlobalTypeParametersDeclarations(irClass, descriptor.declaredTypeParameters)
@@ -162,7 +162,7 @@ class StandaloneDeclarationGenerator(private val context: GeneratorContext) {
         val irConstructor = IrConstructorImpl(startOffset, endOffset, origin, symbol, IrUninitializedType, descriptor)
         irConstructor.metadata = MetadataSource.Function(descriptor)
 
-        symbolTable.withScope(descriptor) {
+        symbolTable.withScope(irConstructor) {
             val ctorTypeParameters = descriptor.typeParameters.filter { it.containingDeclaration === descriptor }
             generateScopedTypeParameterDeclarations(irConstructor, ctorTypeParameters)
             generateValueParameterDeclarations(irConstructor, descriptor, defaultArgumentFactory)

compiler/ir/ir.tree/build.gradle.kts

@@ -13,12 +13,4 @@ dependencies {
 sourceSets {
     "main" { projectDefault() }
     "test" {}
-}
-
-tasks {
-    val compileKotlin by existing(org.jetbrains.kotlin.gradle.tasks.KotlinCompile::class) {
-        kotlinOptions {
-            freeCompilerArgs += "-Xopt-in=org.jetbrains.kotlin.ir.DescriptorBasedIr"
-        }
-    }
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/builders/ExpressionHelpers.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.ir.expressions.impl.*
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.parentAsClass
+import org.jetbrains.kotlin.ir.util.render
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.utils.addToStdlib.assertedCast
 
@@ -45,12 +46,6 @@ fun <T : IrElement> IrStatementsBuilder<T>.irTemporary(
     return temporary
 }
 
-fun <T : IrElement> IrStatementsBuilder<T>.defineTemporary(value: IrExpression, nameHint: String? = null): VariableDescriptor {
-    val temporary = scope.createTemporaryVariable(value, nameHint)
-    +temporary
-    return temporary.descriptor
-}
-
 fun <T : IrElement> IrStatementsBuilder<T>.irTemporaryVarDeclaration(
     type: IrType,
     nameHint: String? = null,
@@ -72,12 +67,6 @@ fun <T : IrElement> IrStatementsBuilder<T>.irTemporaryVar(
 }
 
 
-fun <T : IrElement> IrStatementsBuilder<T>.defineTemporaryVar(value: IrExpression, nameHint: String? = null): VariableDescriptor {
-    val temporary = scope.createTemporaryVariable(value, nameHint, isMutable = true)
-    +temporary
-    return temporary.descriptor
-}
-
 fun IrBuilderWithScope.irExprBody(value: IrExpression) =
     IrExpressionBodyImpl(startOffset, endOffset, value)
 
@@ -89,7 +78,7 @@ fun IrBuilderWithScope.irReturn(value: IrExpression) =
         startOffset, endOffset,
         context.irBuiltIns.nothingType,
         scope.scopeOwnerSymbol.assertedCast<IrReturnTargetSymbol> {
-            "Function scope expected: ${scope.scopeOwner}"
+            "Function scope expected: ${scope.scopeOwnerSymbol.owner.render()}"
         },
         value
     )
@@ -240,11 +229,29 @@ fun IrBuilderWithScope.irCallConstructor(callee: IrConstructorSymbol, typeArgume
         }
     }
 
-fun IrBuilderWithScope.irCall(callee: IrSimpleFunctionSymbol, type: IrType): IrCall =
+fun IrBuilderWithScope.irCall(
-    IrCallImpl(startOffset, endOffset, type, callee)
+    callee: IrSimpleFunctionSymbol,
+    type: IrType,
+    valueArgumentsCount: Int = callee.owner.valueParameters.size,
+    typeArgumentsCount: Int = callee.owner.typeParameters.size
+): IrCall =
+    IrCallImpl(
+        startOffset, endOffset, type, callee,
+        typeArgumentsCount = typeArgumentsCount,
+        valueArgumentsCount = valueArgumentsCount
+    )
 
-fun IrBuilderWithScope.irCall(callee: IrConstructorSymbol, type: IrType): IrConstructorCall =
+fun IrBuilderWithScope.irCall(
-    IrConstructorCallImpl.fromSymbolDescriptor(startOffset, endOffset, type, callee)
+    callee: IrConstructorSymbol,
+    type: IrType,
+    constructedClass: IrClass = callee.owner.parentAsClass
+): IrConstructorCall =
+    IrConstructorCallImpl(
+        startOffset, endOffset, type, callee,
+        valueArgumentsCount = callee.owner.valueParameters.size,
+        typeArgumentsCount = callee.owner.typeParameters.size + constructedClass.typeParameters.size,
+        constructorTypeArgumentsCount = callee.owner.typeParameters.size
+    )
 
 fun IrBuilderWithScope.irCall(callee: IrFunctionSymbol, type: IrType): IrFunctionAccessExpression =
     when (callee) {
@@ -263,7 +270,12 @@ fun IrBuilderWithScope.irCall(callee: IrFunctionSymbol): IrFunctionAccessExpress
     irCall(callee, callee.owner.returnType)
 
 fun IrBuilderWithScope.irCall(callee: IrFunctionSymbol, descriptor: FunctionDescriptor, type: IrType): IrCall =
-    IrCallImpl(startOffset, endOffset, type, callee as IrSimpleFunctionSymbol)
+    IrCallImpl(
+        startOffset, endOffset, type,
+        callee as IrSimpleFunctionSymbol,
+        valueArgumentsCount = callee.owner.valueParameters.size,
+        typeArgumentsCount = callee.owner.typeParameters.size
+    )
 
 fun IrBuilderWithScope.irCall(callee: IrFunction): IrFunctionAccessExpression =
     irCall(callee.symbol)
@@ -283,12 +295,12 @@ fun IrBuilderWithScope.irDelegatingConstructorCall(callee: IrConstructor): IrDel
     )
 
 fun IrBuilderWithScope.irCallOp(
-    callee: IrFunctionSymbol,
+    callee: IrSimpleFunctionSymbol,
     type: IrType,
     dispatchReceiver: IrExpression,
     argument: IrExpression? = null
 ): IrMemberAccessExpression =
-    irCall(callee, type).apply {
+    irCall(callee, type, valueArgumentsCount = if (argument != null) 1 else 0, typeArgumentsCount = 0).apply {
         this.dispatchReceiver = dispatchReceiver
         if (argument != null)
             putValueArgument(0, argument)

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/builders/Primitives.kt

@@ -33,7 +33,12 @@ fun primitiveOp1(
     origin: IrStatementOrigin,
     dispatchReceiver: IrExpression
 ): IrExpression =
-    IrCallImpl(startOffset, endOffset, primitiveOpReturnType, primitiveOpSymbol, origin = origin).also {
+    IrCallImpl(
+        startOffset, endOffset, primitiveOpReturnType, primitiveOpSymbol,
+        typeArgumentsCount = 0,
+        valueArgumentsCount = 0,
+        origin = origin
+    ).also {
         it.dispatchReceiver = dispatchReceiver
     }
 
@@ -47,7 +52,8 @@ fun primitiveOp2(
     IrCallImpl(
         startOffset, endOffset,
         primitiveOpReturnType,
-        primitiveOpSymbol, typeArgumentsCount = 0,
+        primitiveOpSymbol,
+        typeArgumentsCount = 0,
         valueArgumentsCount = 2,
         origin = origin
     ).apply {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/builders/Scope.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.builders
 
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
@@ -34,7 +35,9 @@ import org.jetbrains.kotlin.ir.types.toKotlinType
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.types.KotlinType
 
+@OptIn(DescriptorBasedIr::class)
 class Scope(val scopeOwnerSymbol: IrSymbol) {
+    @DescriptorBasedIr
     val scopeOwner: DeclarationDescriptor get() = scopeOwnerSymbol.descriptor
 
     fun getLocalDeclarationParent(): IrDeclarationParent {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/builders/ScopeHelpers.kt

@@ -1,36 +0,0 @@
-/*
- * 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.
- */
-
-package org.jetbrains.kotlin.ir.builders
-
-import org.jetbrains.kotlin.descriptors.ClassDescriptor
-import org.jetbrains.kotlin.descriptors.FunctionDescriptor
-import org.jetbrains.kotlin.descriptors.MemberDescriptor
-
-inline fun <reified T> Scope.assertCastOwner() =
-    scopeOwner as? T ?: throw AssertionError("Unexpected scopeOwner: $scopeOwner")
-
-fun Scope.functionOwner(): FunctionDescriptor =
-    assertCastOwner()
-
-fun Scope.classOwner(): ClassDescriptor =
-    scopeOwner.let {
-        when (it) {
-            is ClassDescriptor -> it
-            is MemberDescriptor -> it.containingDeclaration as ClassDescriptor
-            else -> throw AssertionError("Unexpected scopeOwner: $scopeOwner")
-        }
-    }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrAnonymousInitializer.kt

@@ -17,10 +17,12 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.expressions.IrBlockBody
 import org.jetbrains.kotlin.ir.symbols.IrAnonymousInitializerSymbol
 
 interface IrAnonymousInitializer : IrSymbolDeclaration<IrAnonymousInitializerSymbol> {
+    @DescriptorBasedIr
     override val descriptor: ClassDescriptor // TODO special descriptor for anonymous initializer blocks
     val isStatic: Boolean
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrClass.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.ir.declarations
 
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.types.IrType
@@ -24,6 +25,7 @@ interface IrClass :
     IrSymbolDeclaration<IrClassSymbol>, IrDeclarationWithName, IrDeclarationWithVisibility,
     IrDeclarationContainer, IrTypeParametersContainer, IrAttributeContainer {
 
+    @DescriptorBasedIr
     override val descriptor: ClassDescriptor
 
     override var visibility: Visibility

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrConstructor.kt

@@ -18,10 +18,12 @@ package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.ClassConstructorDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.symbols.IrConstructorSymbol
 
 
 interface IrConstructor : IrFunction, IrSymbolDeclaration<IrConstructorSymbol> {
+    @DescriptorBasedIr
     override val descriptor: ClassConstructorDescriptor
 
     override var visibility: Visibility

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrEnumEntry.kt

@@ -17,10 +17,12 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 import org.jetbrains.kotlin.ir.symbols.IrEnumEntrySymbol
 
 interface IrEnumEntry : IrSymbolDeclaration<IrEnumEntrySymbol>, IrDeclarationWithName {
+    @DescriptorBasedIr
     override val descriptor: ClassDescriptor
 
     var correspondingClass: IrClass?

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrField.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 import org.jetbrains.kotlin.ir.symbols.IrFieldSymbol
 import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
@@ -15,6 +16,7 @@ interface IrField :
     IrSymbolDeclaration<IrFieldSymbol>, IrOverridableDeclaration<IrFieldSymbol>,
     IrDeclarationWithName, IrDeclarationWithVisibility, IrDeclarationParent {
 
+    @DescriptorBasedIr
     override val descriptor: PropertyDescriptor
 
     val type: IrType

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrFunction.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.expressions.IrBody
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
@@ -26,6 +27,7 @@ import org.jetbrains.kotlin.ir.types.IrType
 interface IrFunction :
     IrDeclarationWithName, IrDeclarationWithVisibility, IrTypeParametersContainer, IrSymbolOwner, IrDeclarationParent, IrReturnTarget {
 
+    @DescriptorBasedIr
     override val descriptor: FunctionDescriptor
     override val symbol: IrFunctionSymbol
 
@@ -44,7 +46,7 @@ interface IrFunction :
     override val metadata: MetadataSource?
 }
 
-
+@DescriptorBasedIr
 fun IrFunction.getIrValueParameter(parameter: ValueParameterDescriptor): IrValueParameter =
     valueParameters.getOrElse(parameter.index) {
         throw AssertionError("No IrValueParameter for $parameter")
@@ -54,9 +56,7 @@ fun IrFunction.getIrValueParameter(parameter: ValueParameterDescriptor): IrValue
         }
     }
 
-fun IrFunction.getDefault(parameter: ValueParameterDescriptor): IrExpressionBody? =
+@DescriptorBasedIr
-    getIrValueParameter(parameter).defaultValue
-
 fun IrFunction.putDefault(parameter: ValueParameterDescriptor, expressionBody: IrExpressionBody) {
     getIrValueParameter(parameter).defaultValue = expressionBody
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrLocalDelegatedProperty.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.VariableDescriptorWithAccessors
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.symbols.IrLocalDelegatedPropertySymbol
 import org.jetbrains.kotlin.ir.symbols.IrSymbol
 import org.jetbrains.kotlin.ir.types.IrType
@@ -25,6 +26,7 @@ interface IrLocalDelegatedProperty :
     IrDeclarationWithName,
     IrSymbolOwner {
 
+    @DescriptorBasedIr
     override val descriptor: VariableDescriptorWithAccessors
     override val symbol: IrLocalDelegatedPropertySymbol
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrProperty.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 
@@ -27,6 +28,7 @@ interface IrProperty :
     IrOverridableMember,
     IrSymbolOwner {
 
+    @DescriptorBasedIr
     override val descriptor: PropertyDescriptor
     override val symbol: IrPropertySymbol
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrReturnTarget.kt

@@ -6,9 +6,12 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.symbols.IrReturnTargetSymbol
 
 interface IrReturnTarget : IrSymbolOwner {
+    @DescriptorBasedIr
     val descriptor: FunctionDescriptor
+
     override val symbol: IrReturnTargetSymbol
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeAlias.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.TypeAliasDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.symbols.IrTypeAliasSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 
@@ -15,7 +16,9 @@ interface IrTypeAlias :
     IrDeclarationWithVisibility,
     IrTypeParametersContainer {
 
+    @DescriptorBasedIr
     override val descriptor: TypeAliasDescriptor
+
     val isActual: Boolean
     val expandedType: IrType
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrTypeParameter.kt

@@ -17,12 +17,14 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.types.Variance
 
 interface IrTypeParameter : IrSymbolDeclaration<IrTypeParameterSymbol>, IrDeclarationWithName {
+    @DescriptorBasedIr
     override val descriptor: TypeParameterDescriptor
 
     val variance: Variance

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueDeclaration.kt

@@ -6,12 +6,14 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.ValueDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.symbols.IrValueSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 
 interface IrValueDeclaration : IrDeclarationWithName, IrSymbolOwner {
+    @DescriptorBasedIr
     override val descriptor: ValueDescriptor
-    override val symbol: IrValueSymbol
 
+    override val symbol: IrValueSymbol
     val type: IrType
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrValueParameter.kt

@@ -17,12 +17,14 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.ParameterDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 import org.jetbrains.kotlin.ir.symbols.IrValueParameterSymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 
 interface IrValueParameter : IrValueDeclaration, IrSymbolDeclaration<IrValueParameterSymbol> {
+    @DescriptorBasedIr
     override val descriptor: ParameterDescriptor
 
     val index: Int

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrVariable.kt

@@ -17,10 +17,12 @@
 package org.jetbrains.kotlin.ir.declarations
 
 import org.jetbrains.kotlin.descriptors.VariableDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.symbols.IrVariableSymbol
 
 interface IrVariable : IrValueDeclaration, IrSymbolDeclaration<IrVariableSymbol> {
+    @DescriptorBasedIr
     override val descriptor: VariableDescriptor
 
     val isVar: Boolean

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrAnonymousInitializerImpl.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrAnonymousInitializer
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.AnonymousInitializerCarrier
@@ -39,6 +40,7 @@ class IrAnonymousInitializerImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val descriptor: ClassDescriptor get() = symbol.descriptor
 
     override var bodyField: IrBlockBody? = null

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrClassImpl.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.ClassCarrier
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
@@ -76,6 +77,7 @@ class IrClassImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val descriptor: ClassDescriptor get() = symbol.descriptor
 
     override var visibilityField: Visibility = visibility

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrConstructorImpl.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.ClassConstructorDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.ConstructorCarrier
 import org.jetbrains.kotlin.ir.symbols.IrConstructorSymbol
@@ -70,6 +71,7 @@ class IrConstructorImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val descriptor: ClassConstructorDescriptor get() = symbol.descriptor
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrEnumEntryImpl.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrEnumEntry
@@ -42,6 +43,7 @@ class IrEnumEntryImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val descriptor: ClassDescriptor get() = symbol.descriptor
 
     override var correspondingClassField: IrClass? = null

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrErrorDeclarationImpl.kt

@@ -17,12 +17,14 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrErrorDeclaration
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.ErrorCarrier
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
+@OptIn(DescriptorBasedIr::class)
 class IrErrorDeclarationImpl(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrExternalPackageFragmentImpl.kt

@@ -19,6 +19,7 @@ package org.jetbrains.kotlin.ir.declarations.impl
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.descriptors.impl.EmptyPackageFragmentDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElementBase
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
@@ -40,10 +41,12 @@ class IrExternalPackageFragmentImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val packageFragmentDescriptor: PackageFragmentDescriptor get() = symbol.descriptor
 
     override val declarations: MutableList<IrDeclaration> = ArrayList()
 
+    @OptIn(DescriptorBasedIr::class)
     override val containerSource get() = (symbol.descriptor as? DeserializedMemberDescriptor)?.containerSource
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFieldImpl.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.FieldCarrier
 import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
@@ -69,6 +70,7 @@ class IrFieldImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val descriptor: PropertyDescriptor = symbol.descriptor
 
     override var initializerField: IrExpressionBody? = null

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFileImpl.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElementBase
 import org.jetbrains.kotlin.ir.SourceManager
 import org.jetbrains.kotlin.ir.declarations.*
@@ -44,6 +45,7 @@ class IrFileImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val packageFragmentDescriptor: PackageFragmentDescriptor get() = symbol.descriptor
 
     override val declarations: MutableList<IrDeclaration> = ArrayList()

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrFunctionImpl.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.ir.declarations.impl
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.FunctionCarrier
 import org.jetbrains.kotlin.ir.descriptors.WrappedSimpleFunctionDescriptor
@@ -38,6 +39,7 @@ abstract class IrFunctionCommonImpl(
     IrSimpleFunction,
     FunctionCarrier {
 
+    @DescriptorBasedIr
     abstract override val descriptor: FunctionDescriptor
 
     override var overriddenSymbolsField: List<IrSimpleFunctionSymbol> = emptyList()
@@ -127,6 +129,7 @@ class IrFunctionImpl(
         IrSimpleFunctionSymbolImpl(descriptor), returnType, descriptor
     )
 
+    @DescriptorBasedIr
     override val descriptor: FunctionDescriptor get() = symbol.descriptor
 
     init {
@@ -160,9 +163,11 @@ class IrFakeOverrideFunctionImpl(
     override val symbol: IrSimpleFunctionSymbol
         get() = _symbol ?: error("$this has not acquired a symbol yet")
 
-    override val descriptor get() =
+    @DescriptorBasedIr
-        _symbol?.descriptor ?: WrappedSimpleFunctionDescriptor()
+    override val descriptor
+        get() = _symbol?.descriptor ?: WrappedSimpleFunctionDescriptor()
 
+    @OptIn(DescriptorBasedIr::class)
     fun acquireSymbol(symbol: IrSimpleFunctionSymbol) {
         assert(_symbol == null) { "$this already has symbol _symbol" }
         _symbol = symbol

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrLocalDelegatedPropertyImpl.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.VariableDescriptorWithAccessors
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.LocalDelegatedPropertyCarrier
 import org.jetbrains.kotlin.ir.symbols.IrLocalDelegatedPropertySymbol
@@ -44,6 +45,7 @@ class IrLocalDelegatedPropertyImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val descriptor: VariableDescriptorWithAccessors
         get() = symbol.descriptor
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrPropertyImpl.kt

@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.PropertyCarrier
 import org.jetbrains.kotlin.ir.descriptors.WrappedPropertyDescriptor
@@ -49,6 +50,7 @@ abstract class IrPropertyCommonImpl(
     IrProperty,
     PropertyCarrier {
 
+    @DescriptorBasedIr
     abstract override val descriptor: PropertyDescriptor
 
     override var backingFieldField: IrField? = null
@@ -214,6 +216,8 @@ class IrPropertyImpl(
     init {
         symbol.bind(this)
     }
+
+    @DescriptorBasedIr
     override val descriptor: PropertyDescriptor = symbol.descriptor
 }
 
@@ -238,9 +242,11 @@ class IrFakeOverridePropertyImpl(
     override val symbol: IrPropertySymbol
         get() = _symbol ?: error("$this has not acquired a symbol yet")
 
-    override val descriptor get() =
+    @DescriptorBasedIr
-        _symbol?.descriptor ?: WrappedPropertyDescriptor()
+    override val descriptor
+        get() = _symbol?.descriptor ?: WrappedPropertyDescriptor()
 
+    @OptIn(DescriptorBasedIr::class)
     fun acquireSymbol(symbol: IrPropertySymbol) {
         assert(_symbol == null) { "$this already has symbol _symbol" }
         _symbol = symbol

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrScriptImpl.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.ScriptDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.declarations.*
@@ -42,6 +43,8 @@ class IrScriptImpl(
     override val statements: MutableList<IrStatement> = mutableListOf()
 
     override lateinit var thisReceiver: IrValueParameter
+
+    @DescriptorBasedIr
     override val descriptor: ScriptDescriptor = symbol.descriptor
 
     init {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeAliasImpl.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.TypeAliasDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrTypeAlias
 import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
@@ -36,6 +37,7 @@ class IrTypeAliasImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val descriptor: TypeAliasDescriptor
         get() = symbol.descriptor
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrTypeParameterImpl.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.TypeParameterCarrier
@@ -60,6 +61,7 @@ class IrTypeParameterImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val descriptor: TypeParameterDescriptor get() = symbol.descriptor
 
     override val superTypes: MutableList<IrType> = SmartList()

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrValueParameterImpl.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.ParameterDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrValueParameter
 import org.jetbrains.kotlin.ir.declarations.impl.carriers.ValueParameterCarrier
@@ -46,6 +47,7 @@ class IrValueParameterImpl(
     IrValueParameter,
     ValueParameterCarrier {
 
+    @DescriptorBasedIr
     constructor(
         startOffset: Int,
         endOffset: Int,
@@ -64,6 +66,7 @@ class IrValueParameterImpl(
         isNoinline = descriptor.safeAs<ValueParameterDescriptor>()?.isNoinline ?: false
     )
 
+    @DescriptorBasedIr
     override val descriptor: ParameterDescriptor = symbol.descriptor
 
     init {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/impl/IrVariableImpl.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.declarations.impl
 
 import org.jetbrains.kotlin.descriptors.VariableDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationParent
 import org.jetbrains.kotlin.ir.declarations.IrVariable
@@ -84,6 +85,7 @@ class IrVariableImpl(
         symbol.bind(this)
     }
 
+    @DescriptorBasedIr
     override val descriptor: VariableDescriptor get() = symbol.descriptor
 
     override var initializer: IrExpression? = null

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyClass.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.declarations.lazy
 
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.types.IrType
@@ -20,6 +21,7 @@ import org.jetbrains.kotlin.metadata.deserialization.NameResolver
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedClassDescriptor
 
+@OptIn(DescriptorBasedIr::class)
 class IrLazyClass(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyConstructor.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.ir.declarations.lazy
 
 import org.jetbrains.kotlin.descriptors.ClassConstructorDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrConstructor
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
@@ -17,6 +18,7 @@ import org.jetbrains.kotlin.ir.util.withScope
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
 
+@OptIn(DescriptorBasedIr::class)
 class IrLazyConstructor(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyDeclarationBase.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.declarations.lazy
 
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.IrElementBase
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.declarations.*
@@ -16,6 +17,7 @@ import org.jetbrains.kotlin.ir.util.TypeTranslator
 import org.jetbrains.kotlin.resolve.scopes.MemberScope
 import org.jetbrains.kotlin.types.KotlinType
 
+@OptIn(DescriptorBasedIr::class)
 abstract class IrLazyDeclarationBase(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyEnumEntryImpl.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.ir.declarations.lazy
 
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrEnumEntry
@@ -28,6 +29,7 @@ import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
 
+@OptIn(DescriptorBasedIr::class)
 class IrLazyEnumEntryImpl(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyField.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.ir.declarations.lazy
 
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrField
@@ -22,6 +23,7 @@ import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
 
+@OptIn(DescriptorBasedIr::class)
 class IrLazyField(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyFunction.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.ir.declarations.lazy
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
@@ -18,6 +19,7 @@ import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.descriptorUtil.propertyIfAccessor
 
+@OptIn(DescriptorBasedIr::class)
 class IrLazyFunction(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyFunctionBase.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.declarations.lazy
 
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.IrValueParameter
@@ -18,6 +19,7 @@ import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
 
+@OptIn(DescriptorBasedIr::class)
 abstract class IrLazyFunctionBase(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyProperty.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.ir.declarations.lazy
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrField
 import org.jetbrains.kotlin.ir.declarations.IrProperty
@@ -21,6 +22,7 @@ import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.hasBackingField
 
+@OptIn(DescriptorBasedIr::class)
 class IrLazyProperty(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeAlias.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.ir.declarations.lazy
 
 import org.jetbrains.kotlin.descriptors.TypeAliasDescriptor
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrTypeAlias
 import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
@@ -20,6 +21,7 @@ import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
 
+@OptIn(DescriptorBasedIr::class)
 class IrLazyTypeAlias(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/IrLazyTypeParameter.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.declarations.lazy
 
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationOrigin
 import org.jetbrains.kotlin.ir.declarations.IrTypeParameter
 import org.jetbrains.kotlin.ir.declarations.IrTypeParametersContainer
@@ -19,6 +20,7 @@ import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.types.Variance
 
+@OptIn(DescriptorBasedIr::class)
 class IrLazyTypeParameter(
     startOffset: Int,
     endOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/lazy/LazyScopedTypeParametersResolver.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.declarations.lazy
 
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.IrTypeParametersContainer
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 import org.jetbrains.kotlin.ir.util.ReferenceSymbolTable
@@ -26,6 +27,7 @@ class LazyScopedTypeParametersResolver(private val symbolTable: ReferenceSymbolT
         typeParameterScopes.removeFirst()
     }
 
+    @DescriptorBasedIr
     override fun resolveScopedTypeParameter(typeParameterDescriptor: TypeParameterDescriptor): IrTypeParameterSymbol? {
         //Just support accessor scoped symbols resolve in external declaration
         //there should be enough to process only parent typeparameters

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrBuiltIns.kt

@@ -286,8 +286,6 @@ class IrBuiltIns(
 
     val checkNotNullSymbol = defineCheckNotNullOperator()
 
-    val checkNotNull = checkNotNullSymbol.descriptor
-
     private fun TypeConstructor.makeNonNullType() = KotlinTypeFactory.simpleType(Annotations.EMPTY, this, listOf(), false)
     private fun TypeConstructor.makeNullableType() = KotlinTypeFactory.simpleType(Annotations.EMPTY, this, listOf(), true)
 

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrFunctionFactory.kt

@@ -9,6 +9,7 @@ import org.jetbrains.kotlin.builtins.KOTLIN_REFLECT_FQ_NAME
 import org.jetbrains.kotlin.builtins.functions.FunctionClassDescriptor
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
+import org.jetbrains.kotlin.ir.DescriptorBasedIr
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.*
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
@@ -26,6 +27,7 @@ import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.Variance
 
+@OptIn(DescriptorBasedIr::class)
 abstract class IrAbstractFunctionFactory {
 
     abstract fun functionClassDescriptor(arity: Int): FunctionClassDescriptor
@@ -75,6 +77,7 @@ abstract class IrAbstractFunctionFactory {
     }
 }
 
+@OptIn(DescriptorBasedIr::class)
 class IrFunctionFactory(private val irBuiltIns: IrBuiltIns, private val symbolTable: SymbolTable) : IrAbstractFunctionFactory() {
 
     // TODO: Lazieness