[IR] Add isAssignable property to IrValueParameter.

Use it to check that only the value parameters that are explicitly
marked assignable are assigned.

Currently, the only parameters marked assignable are those for
default argument stubs.

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

@@ -356,7 +356,7 @@ internal fun IrDeclarationParent.declareThisReceiverParameter(
         symbolTable.irFactory.createValueParameter(
             startOffset, endOffset, thisOrigin, symbol,
             Name.special("<this>"), -1, thisType,
-            varargElementType = null, isCrossinline = false, isNoinline = false
+            varargElementType = null, isCrossinline = false, isNoinline = false, isAssignable = false
         ).apply {
             this.parent = this@declareThisReceiverParameter
             receiverDescriptor.bind(this)

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

@@ -256,7 +256,7 @@ class Fir2IrDeclarationStorage(
                     startOffset, endOffset, IrDeclarationOrigin.DEFINED, symbol,
                     Name.special("<set-?>"), 0, type,
                     varargElementType = null,
-                    isCrossinline = false, isNoinline = false
+                    isCrossinline = false, isNoinline = false, isAssignable = false
                 ).apply {
                     this.parent = parent
                     descriptor.bind(this)
@@ -843,7 +843,7 @@ class Fir2IrDeclarationStorage(
                     valueParameter.name, index, type,
                     if (!valueParameter.isVararg) null
                     else valueParameter.returnTypeRef.coneType.arrayElementType()?.toIrType(typeContext),
-                    valueParameter.isCrossinline, valueParameter.isNoinline
+                    valueParameter.isCrossinline, valueParameter.isNoinline, false
                 ).apply {
                     descriptor.bind(this)
                     if (valueParameter.defaultValue.let {

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

@@ -274,7 +274,8 @@ internal class AdapterGenerator(
                 type,
                 varargElementType = null,
                 isCrossinline = false,
-                isNoinline = false
+                isNoinline = false,
+                isAssignable = false
             ).also { irAdapterValueParameter ->
                 descriptor.bind(irAdapterValueParameter)
                 irAdapterValueParameter.parent = adapterFunction

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

@@ -281,7 +281,7 @@ class DataClassMembersGenerator(val components: Fir2IrComponents) {
             ) { symbol ->
                 components.irFactory.createValueParameter(
                     UNDEFINED_OFFSET, UNDEFINED_OFFSET, origin, symbol, name, index, type, null,
-                    isCrossinline = false, isNoinline = false
+                    isCrossinline = false, isNoinline = false, isAssignable = false
                 )
             }.apply {
                 parent = irFunction

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

@@ -137,7 +137,10 @@ class CheckIrElementVisitor(
 
     override fun visitSetValue(expression: IrSetValue) {
         super.visitSetValue(expression)
-
+        val declaration = expression.symbol.owner
+        if (declaration is IrValueParameter && !declaration.isAssignable) {
+            reportError(expression, "Assignment to value parameters not marked assignable")
+        }
         expression.ensureTypeIs(irBuiltIns.unitType)
     }
 

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

@@ -126,7 +126,8 @@ fun IrValueParameter.copyTo(
     varargElementType: IrType? = this.varargElementType, // TODO: remapTypeParameters here as well
     defaultValue: IrExpressionBody? = this.defaultValue,
     isCrossinline: Boolean = this.isCrossinline,
-    isNoinline: Boolean = this.isNoinline
+    isNoinline: Boolean = this.isNoinline,
+    isAssignable: Boolean = this.isAssignable
 ): IrValueParameter {
     val descriptor = if (index < 0) {
         WrappedReceiverParameterDescriptor()
@@ -143,7 +144,7 @@ fun IrValueParameter.copyTo(
     }
     return factory.createValueParameter(
         startOffset, endOffset, origin, symbol,
-        name, index, type, varargElementType, isCrossinline, isNoinline
+        name, index, type, varargElementType, isCrossinline, isNoinline, isAssignable = isAssignable
     ).also {
         descriptor.bind(it)
         it.parent = irFunction
@@ -171,7 +172,7 @@ fun IrFunction.copyReceiverParametersFrom(from: IrFunction) {
             startOffset, endOffset, origin,
             IrValueParameterSymbolImpl(newDescriptor),
             name,
-            index, type, varargElementType, isCrossinline, isNoinline
+            index, type, varargElementType, isCrossinline, isNoinline, false
         ).also { parameter ->
             parameter.parent = this@copyReceiverParametersFrom
             newDescriptor.bind(this)
@@ -422,6 +423,7 @@ fun IrFunction.createDispatchReceiverParameter(origin: IrDeclarationOrigin? = nu
         parentAsClass.defaultType,
         null,
         false,
+        false,
         false
     ).apply {
         parent = this@createDispatchReceiverParameter

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

@@ -586,7 +586,8 @@ private fun IrFunction.generateDefaultsFunctionImpl(
             type = if (makeNullable) newType.makeNullable() else newType,
             defaultValue = if (it.defaultValue != null) {
                 factory.createExpressionBody(IrErrorExpressionImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET, it.type, "Default Stub"))
-            } else null
+            } else null,
+            isAssignable = it.defaultValue != null
         )
     }
 

compiler/ir/backend.common/src/org/jetbrains/kotlin/ir/builders/declarations/declarationBuilders.kt

@@ -18,7 +18,6 @@ import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.defaultType
 import org.jetbrains.kotlin.ir.util.parentAsClass
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.serialization.deserialization.descriptors.DescriptorWithContainerSource
 import org.jetbrains.kotlin.types.Variance
 
 @PublishedApi
@@ -213,7 +212,7 @@ fun <D> buildReceiverParameter(
     parent.factory.createValueParameter(
         startOffset, endOffset, origin,
         IrValueParameterSymbolImpl(wrappedDescriptor),
-        RECEIVER_PARAMETER_NAME, -1, type, null, isCrossinline = false, isNoinline = false
+        RECEIVER_PARAMETER_NAME, -1, type, null, isCrossinline = false, isNoinline = false, isAssignable = false
     ).also {
         wrappedDescriptor.bind(it)
         it.parent = parent
@@ -227,7 +226,7 @@ internal fun IrFactory.buildValueParameter(builder: IrValueParameterBuilder, par
         return createValueParameter(
             startOffset, endOffset, origin,
             IrValueParameterSymbolImpl(wrappedDescriptor),
-            name, index, type, varargElementType, isCrossInline, isNoinline, isHidden
+            name, index, type, varargElementType, isCrossInline, isNoinline, isHidden, false
         ).also {
             wrappedDescriptor.bind(it)
             it.parent = parent

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

@@ -415,7 +415,7 @@ private fun StatementGenerator.createFunctionForSuspendConversion(
                     Name.identifier("p$index"),
                     index,
                     irParameterType,
-                    varargElementType = null, isCrossinline = false, isNoinline = false
+                    varargElementType = null, isCrossinline = false, isNoinline = false, isAssignable = false
                 )
             }.also {
                 adaptedParameterDescriptor.bind(it)

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

@@ -392,7 +392,7 @@ class ReflectionReferencesGenerator(statementGenerator: StatementGenerator) : St
                 name,
                 index,
                 type.toIrType(),
-                varargElementType = null, isCrossinline = false, isNoinline = false
+                varargElementType = null, isCrossinline = false, isNoinline = false, isAssignable = false
             ).also { irAdapterValueParameter ->
                 descriptor.bind(irAdapterValueParameter)
             }

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

@@ -235,10 +235,11 @@ object IrFactoryImpl : IrFactory {
         varargElementType: IrType?,
         isCrossinline: Boolean,
         isNoinline: Boolean,
-        isHidden: Boolean
+        isHidden: Boolean,
+        isAssignable: Boolean,
     ): IrValueParameter =
         IrValueParameterImpl(
-            startOffset, endOffset, origin, symbol, name, index, type, varargElementType, isCrossinline, isNoinline, isHidden
+            startOffset, endOffset, origin, symbol, name, index, type, varargElementType, isCrossinline, isNoinline, isHidden, isAssignable
         )
 
     override fun createExpressionBody(

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

@@ -39,7 +39,8 @@ class IrValueParameterImpl(
     override var varargElementType: IrType?,
     override val isCrossinline: Boolean,
     override val isNoinline: Boolean,
-    override val isHidden: Boolean = false
+    override val isHidden: Boolean = false,
+    override val isAssignable: Boolean = false
 ) : IrValueParameter() {
     @ObsoleteDescriptorBasedAPI
     override val descriptor: ParameterDescriptor

compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrFactory.kt

@@ -237,10 +237,11 @@ object PersistentIrFactory : IrFactory {
         varargElementType: IrType?,
         isCrossinline: Boolean,
         isNoinline: Boolean,
-        isHidden: Boolean
+        isHidden: Boolean,
+        isAssignable: Boolean
     ): IrValueParameter =
         PersistentIrValueParameter(
-            startOffset, endOffset, origin, symbol, name, index, type, varargElementType, isCrossinline, isNoinline, isHidden
+            startOffset, endOffset, origin, symbol, name, index, type, varargElementType, isCrossinline, isNoinline, isHidden, isAssignable
         )
 
     override fun createExpressionBody(

compiler/ir/ir.tree.persistent/src/org/jetbrains/kotlin/ir/declarations/persistent/PersistentIrValueParameter.kt

@@ -41,7 +41,8 @@ internal class PersistentIrValueParameter(
     varargElementType: IrType?,
     override val isCrossinline: Boolean,
     override val isNoinline: Boolean,
-    override val isHidden: Boolean = false
+    override val isHidden: Boolean = false,
+    override val isAssignable: Boolean
 ) : IrValueParameter(),
     PersistentIrDeclarationBase<ValueParameterCarrier>,
     ValueParameterCarrier {

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

@@ -199,7 +199,8 @@ interface IrFactory {
         varargElementType: IrType?,
         isCrossinline: Boolean,
         isNoinline: Boolean,
-        isHidden: Boolean = false
+        isHidden: Boolean = false,
+        isAssignable: Boolean = false
     ): IrValueParameter
 
     // Bodies

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

@@ -39,6 +39,11 @@ abstract class IrValueParameter : IrValueDeclaration(), IrSymbolDeclaration<IrVa
     // Once we are able to load any top-level declaration from klib this hack should be deprecated and removed.
     abstract val isHidden: Boolean
 
+    // Parameters are not assignable by default. However, in the IR, assignments to parameters are used
+    // to implement default argument stubs. If the default value is to be used, the value is assigned
+    // to the parameter.
+    abstract val isAssignable: Boolean
+
     abstract var defaultValue: IrExpressionBody?
 
     override fun <R, D> accept(visitor: IrElementVisitor<R, D>, data: D): R =

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

@@ -32,7 +32,7 @@ interface IrLazyDeclarationBase : IrDeclaration {
     fun ReceiverParameterDescriptor.generateReceiverParameterStub(): IrValueParameter =
         factory.createValueParameter(
             UNDEFINED_OFFSET, UNDEFINED_OFFSET, origin, IrValueParameterSymbolImpl(this),
-            name, -1, type.toIrType(), null, isCrossinline = false, isNoinline = false
+            name, -1, type.toIrType(), null, isCrossinline = false, isNoinline = false, isAssignable = false
         )
 
     fun generateMemberStubs(memberScope: MemberScope, container: MutableList<IrDeclaration>) {

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

@@ -80,7 +80,7 @@ class IrBuiltIns(
                 val valueParameterSymbol = IrValueParameterSymbolImpl(valueParameterDescriptor)
                 irFactory.createValueParameter(
                     UNDEFINED_OFFSET, UNDEFINED_OFFSET, BUILTIN_OPERATOR, valueParameterSymbol, Name.identifier("arg$i"), i,
-                    valueParameterType, null, isCrossinline = false, isNoinline = false
+                    valueParameterType, null, isCrossinline = false, isNoinline = false, isAssignable = false
                 ).apply {
                     parent = operator
                 }
@@ -165,7 +165,7 @@ class IrBuiltIns(
             val valueParameterSymbol = IrValueParameterSymbolImpl(valueParameterDescriptor)
             val valueParameter = irFactory.createValueParameter(
                 UNDEFINED_OFFSET, UNDEFINED_OFFSET, BUILTIN_OPERATOR, valueParameterSymbol, Name.identifier("arg0"), 0,
-                valueIrType, null, isCrossinline = false, isNoinline = false
+                valueIrType, null, isCrossinline = false, isNoinline = false, isAssignable = false
             )
 
             valueParameter.parent = operator

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

@@ -268,7 +268,8 @@ class IrFunctionFactory(private val irBuiltIns: IrBuiltIns, private val symbolTa
         val vDeclaration = irFactory.createValueParameter(
             offset, offset, classOrigin, vSymbol, Name.special("<this>"), -1, type, null,
             isCrossinline = false,
-            isNoinline = false
+            isNoinline = false,
+            isAssignable = false
         )
 
         if (vDescriptor is WrappedReceiverParameterDescriptor) vDescriptor.bind(vDeclaration)
@@ -332,7 +333,8 @@ class IrFunctionFactory(private val irBuiltIns: IrBuiltIns, private val symbolTa
                 val vDeclaration = irFactory.createValueParameter(
                     offset, offset, memberOrigin, vSymbol, Name.identifier("p$i"), i - 1, vType, null,
                     isCrossinline = false,
-                    isNoinline = false
+                    isNoinline = false,
+                    isAssignable = false
                 )
                 vDeclaration.parent = fDeclaration
                 if (vDescriptor is WrappedValueParameterDescriptor) vDescriptor.bind(vDeclaration)

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/overrides/FakeOverrideCopier.kt

@@ -95,7 +95,8 @@ class FakeOverrideCopier(
             declaration.type.remapType(),
             declaration.varargElementType?.remapType(),
             declaration.isCrossinline,
-            declaration.isNoinline
+            declaration.isNoinline,
+            false
         ).apply {
             transformAnnotations(declaration)
             // Don't set the default value for fake overrides.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/DeclarationStubGenerator.kt

@@ -242,7 +242,7 @@ class DeclarationStubGenerator(
     internal fun generateValueParameterStub(descriptor: ValueParameterDescriptor): IrValueParameter = with(descriptor) {
         symbolTable.irFactory.createValueParameter(
             UNDEFINED_OFFSET, UNDEFINED_OFFSET, computeOrigin(this), IrValueParameterSymbolImpl(this), name, index, type.toIrType(),
-            varargElementType?.toIrType(), isCrossinline, isNoinline
+            varargElementType?.toIrType(), isCrossinline, isNoinline, false
         ).also { irValueParameter ->
             if (descriptor.declaresDefaultValue()) {
                 irValueParameter.defaultValue =

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/DeepCopyIrTreeWithSymbols.kt

@@ -348,7 +348,8 @@ open class DeepCopyIrTreeWithSymbols(
             declaration.type.remapType(),
             declaration.varargElementType?.remapType(),
             declaration.isCrossinline,
-            declaration.isNoinline
+            declaration.isNoinline,
+            false
         ).apply {
             transformAnnotations(declaration)
             defaultValue = declaration.defaultValue?.transform()

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/RenderIrElement.kt

@@ -524,7 +524,7 @@ class RenderIrElementVisitor(private val normalizeNames: Boolean = false) : IrEl
         renderFlagsList(
             "vararg".takeIf { varargElementType != null },
             "crossinline".takeIf { isCrossinline },
-            "noinline".takeIf { isNoinline }
+            "noinline".takeIf { isNoinline },
         )
 
     override fun visitLocalDelegatedProperty(declaration: IrLocalDelegatedProperty, data: Nothing?): String =

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/SymbolTable.kt

@@ -896,7 +896,7 @@ class SymbolTable(
         valueParameterFactory: (IrValueParameterSymbol) -> IrValueParameter = {
             irFactory.createValueParameter(
                 startOffset, endOffset, origin, it, nameProvider.nameForDeclaration(descriptor),
-                descriptor.indexOrMinusOne, type, varargElementType, descriptor.isCrossinline, descriptor.isNoinline
+                descriptor.indexOrMinusOne, type, varargElementType, descriptor.isCrossinline, descriptor.isNoinline, false
             )
         }
     ): IrValueParameter =

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/IrFileDeserializer.kt

@@ -1009,7 +1009,8 @@ abstract class IrFileDeserializer(
                 if (proto.hasVarargElementType()) deserializeIrType(proto.varargElementType) else null,
                 flags.isCrossInline,
                 flags.isNoInline,
-                flags.isHidden
+                flags.isHidden,
+                false
             ).apply {
                 if (proto.hasDefaultValue())
                     defaultValue = irFactory.createExpressionBody(deserializeExpressionBody(proto.defaultValue))

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/GeneratorHelpers.kt

@@ -379,7 +379,7 @@ interface IrBuilderExtension {
         fun irValueParameter(descriptor: ParameterDescriptor): IrValueParameter = with(descriptor) {
             factory.createValueParameter(
                 function.startOffset, function.endOffset, SERIALIZABLE_PLUGIN_ORIGIN, IrValueParameterSymbolImpl(this),
-                name, indexOrMinusOne, type.toIrType(), varargElementType?.toIrType(), isCrossinline, isNoinline
+                name, indexOrMinusOne, type.toIrType(), varargElementType?.toIrType(), isCrossinline, isNoinline, false
             ).also {
                 it.parent = function
             }