JVM_IR: deal with inline class default values in AddContinuationLowering.

Whenever we want the default 0/null value for a type we need to
check if it is a non-nullable inline class type and produce
the right value for the underlying type.

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

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.backend.jvm.codegen.isInlineOnly
 import org.jetbrains.kotlin.backend.jvm.codegen.isJvmInterface
 import org.jetbrains.kotlin.backend.jvm.descriptors.JvmDeclarationFactory
 import org.jetbrains.kotlin.backend.jvm.lower.inlineclasses.hasMangledParameters
+import org.jetbrains.kotlin.backend.jvm.lower.inlineclasses.unboxInlineClass
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
@@ -20,6 +21,8 @@ import org.jetbrains.kotlin.ir.builders.Scope
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.expressions.*
+import org.jetbrains.kotlin.ir.expressions.impl.IrCallImpl
+import org.jetbrains.kotlin.ir.expressions.impl.IrConstImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetFieldImpl
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.IrSymbol
@@ -88,6 +91,25 @@ val IrType.erasedUpperBound: IrClass
         else -> throw IllegalStateException()
     }
 
+/**
+ * Get the default null/0 value for the type.
+ *
+ * This handles unboxing of non-nullable inline class types to their underlying types and produces
+ * a null/0 default value for the resulting type. When such unboxing takes place it ensures that
+ * the value is not reboxed and reunboxed by the codegen by using the unsafeCoerceIntrinsic.
+ */
+fun IrType.defaultValue(startOffset: Int, endOffset: Int, context: JvmBackendContext): IrExpression {
+    if (this !is IrSimpleType || hasQuestionMark || classOrNull?.owner?.isInline != true)
+        return IrConstImpl.defaultValueForType(startOffset, endOffset, this)
+
+    val underlyingType = unboxInlineClass()
+    val defaultValueForUnderlyingType = IrConstImpl.defaultValueForType(startOffset, endOffset, underlyingType)
+    return IrCallImpl(startOffset, endOffset, this, context.ir.symbols.unsafeCoerceIntrinsic).also {
+        it.putTypeArgument(0, underlyingType) // from
+        it.putTypeArgument(1, this) // to
+        it.putValueArgument(0, defaultValueForUnderlyingType)
+    }
+}
 
 fun IrDeclaration.getJvmNameFromAnnotation(): String? {
     // TODO lower @JvmName?

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

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.backend.common.phaser.makeIrFilePhase
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
 import org.jetbrains.kotlin.backend.jvm.JvmLoweredDeclarationOrigin
 import org.jetbrains.kotlin.backend.jvm.ir.IrInlineReferenceLocator
+import org.jetbrains.kotlin.backend.jvm.ir.defaultValue
 import org.jetbrains.kotlin.codegen.coroutines.*
 import org.jetbrains.kotlin.codegen.inline.coroutines.FOR_INLINE_SUFFIX
 import org.jetbrains.kotlin.descriptors.Modality
@@ -23,7 +24,6 @@ import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.builders.declarations.*
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
-import org.jetbrains.kotlin.ir.expressions.impl.IrConstImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetFieldImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrReturnImpl
@@ -446,6 +446,7 @@ private class AddContinuationLowering(private val context: JvmBackendContext) :
         capturedThisField: IrField?,
         isStaticSuspendImpl: Boolean
     ) {
+        val backendContext = context
         val invokeSuspend = context.ir.symbols.continuationImplClass.owner.functions
             .single { it.name == Name.identifier(INVOKE_SUSPEND_METHOD_NAME) }
         addFunctionOverride(invokeSuspend).also { function ->
@@ -481,15 +482,12 @@ private class AddContinuationLowering(private val context: JvmBackendContext) :
                         it.dispatchReceiver = capturedThisValue
                     }
                     irFunction.extensionReceiverParameter?.let { extensionReceiverParameter ->
-                        it.extensionReceiver = IrConstImpl.defaultValueForType(
-                            UNDEFINED_OFFSET, UNDEFINED_OFFSET, extensionReceiverParameter.type
+                        it.extensionReceiver = extensionReceiverParameter.type.defaultValue(
+                            UNDEFINED_OFFSET, UNDEFINED_OFFSET, backendContext
                         )
                     }
                     for ((i, parameter) in irFunction.valueParameters.withIndex()) {
-                        val defaultValueForParameter = IrConstImpl.defaultValueForType(
-                            UNDEFINED_OFFSET, UNDEFINED_OFFSET, parameter.type
-                        )
-                        it.putValueArgument(i, defaultValueForParameter)
+                        it.putValueArgument(i, parameter.type.defaultValue(UNDEFINED_OFFSET, UNDEFINED_OFFSET, backendContext))
                     }
                     if (isStaticSuspendImpl) {
                         it.putValueArgument(0, capturedThisValue)
@@ -501,6 +499,7 @@ private class AddContinuationLowering(private val context: JvmBackendContext) :
 
     private fun createStaticSuspendImpl(irFunction: IrSimpleFunction): IrSimpleFunction {
         // Create static suspend impl method.
+        val backendContext = context
         val static = createStaticFunctionWithReceivers(
             irFunction.parent,
             irFunction.name.toSuspendImplementationName(),
@@ -520,12 +519,14 @@ private class AddContinuationLowering(private val context: JvmBackendContext) :
                     it.putValueArgument(i++, irGet(irFunction.dispatchReceiverParameter!!))
                 }
                 if (irFunction.extensionReceiverParameter != null) {
-                    it.putValueArgument(i++, irNull())
+                    val defaultValueForParameter = irFunction.extensionReceiverParameter!!.type.defaultValue(
+                        UNDEFINED_OFFSET, UNDEFINED_OFFSET, backendContext
+                    )
+                    it.putValueArgument(i++, defaultValueForParameter)
+
                 }
                 for (parameter in irFunction.valueParameters) {
-                    val defaultValueForParameter = IrConstImpl.defaultValueForType(
-                        UNDEFINED_OFFSET, UNDEFINED_OFFSET, parameter.type
-                    )
+                    val defaultValueForParameter = parameter.type.defaultValue(UNDEFINED_OFFSET, UNDEFINED_OFFSET, backendContext)
                     it.putValueArgument(i++, defaultValueForParameter)
                 }
             })

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

@@ -7,15 +7,12 @@ package org.jetbrains.kotlin.backend.jvm.lower
 
 import org.jetbrains.kotlin.backend.common.lower.DefaultParameterInjector
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
+import org.jetbrains.kotlin.backend.jvm.ir.defaultValue
 import org.jetbrains.kotlin.backend.jvm.ir.getJvmVisibilityOfDefaultArgumentStub
-import org.jetbrains.kotlin.backend.jvm.lower.inlineclasses.unboxInlineClass
 import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.IrValueParameter
 import org.jetbrains.kotlin.ir.expressions.IrExpression
-import org.jetbrains.kotlin.ir.expressions.impl.IrCallImpl
-import org.jetbrains.kotlin.ir.types.IrSimpleType
 import org.jetbrains.kotlin.ir.types.IrType
-import org.jetbrains.kotlin.ir.types.classOrNull
 
 class JvmDefaultParameterInjector(context: JvmBackendContext) :
     DefaultParameterInjector(context, skipInline = false, skipExternalMethods = false) {
@@ -26,15 +23,7 @@ class JvmDefaultParameterInjector(context: JvmBackendContext) :
         nullConst(startOffset, endOffset, irParameter.type)
 
     override fun nullConst(startOffset: Int, endOffset: Int, type: IrType): IrExpression {
-        if (type !is IrSimpleType || type.hasQuestionMark || type.classOrNull?.owner?.isInline != true)
-            return super.nullConst(startOffset, endOffset, type)
-
-        val underlyingType = type.unboxInlineClass()
-        return IrCallImpl(startOffset, endOffset, type, context.ir.symbols.unsafeCoerceIntrinsic).apply {
-            putTypeArgument(0, underlyingType) // from
-            putTypeArgument(1, type) // to
-            putValueArgument(0, super.nullConst(startOffset, endOffset, underlyingType))
-        }
+        return type.defaultValue(startOffset, endOffset, context)
     }
 
     override fun defaultArgumentStubVisibility(function: IrFunction) = function.getJvmVisibilityOfDefaultArgumentStub()

compiler/testData/codegen/box/inlineClasses/unboxParameterOfSuspendLambdaBeforeInvoke.kt

@@ -1,7 +1,7 @@
 // IGNORE_BACKEND_FIR: JVM_IR
 // WITH_COROUTINES
 // WITH_RUNTIME
-// IGNORE_BACKEND: JVM_IR, JS_IR
+// IGNORE_BACKEND: JS_IR
 
 import helpers.*
 import kotlin.coroutines.*