JVM IR: Fix types in LateInitLowering

On the JVM backend the throwUninitializedPropertyAccessException
function is implemented in Java and has a return type of Unit instead of
Nothing. In order to make the types match up we have to wrap its call in
a block with an additional IrThrow.

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

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.backend.common.FileLoweringPass
 import org.jetbrains.kotlin.backend.common.descriptors.WrappedVariableDescriptor
 import org.jetbrains.kotlin.backend.common.ir.Symbols
 import org.jetbrains.kotlin.ir.IrStatement
-import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.builders.declarations.buildField
 import org.jetbrains.kotlin.ir.declarations.*
@@ -36,7 +35,7 @@ import org.jetbrains.kotlin.ir.util.resolveFakeOverride
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 
-class LateinitLowering(val context: CommonBackendContext) : FileLoweringPass {
+open class LateinitLowering(val context: CommonBackendContext) : FileLoweringPass {
 
     private val nullableFields = context.lateinitNullableFields
     private fun buildOrGetNullableField(originalField: IrField): IrField {
@@ -117,7 +116,7 @@ class LateinitLowering(val context: CommonBackendContext) : FileLoweringPass {
                         context.irBuiltIns.nothingType,
                         irNotEquals(irGet(resultVar), irNull()),
                         irReturn(irGet(resultVar)),
-                        throwUninitializedPropertyAccessException(backingField.name.asString())
+                        throwUninitializedPropertyAccessException(this, backingField.name.asString())
                     )
                     body.statements.add(throwIfNull)
                     getter.body = body
@@ -136,7 +135,7 @@ class LateinitLowering(val context: CommonBackendContext) : FileLoweringPass {
                 return irBuilder.run {
                     irIfThenElse(
                         expression.type, irEqualsNull(irGet(irVar)),
-                        throwUninitializedPropertyAccessException(irVar.name.asString()),
+                        throwUninitializedPropertyAccessException(this, irVar.name.asString()),
                         irGet(irVar)
                     )
                 }
@@ -185,17 +184,9 @@ class LateinitLowering(val context: CommonBackendContext) : FileLoweringPass {
         })
     }
 
-    private fun IrBuilderWithScope.throwUninitializedPropertyAccessException(name: String) =
-        irCall(throwErrorFunction).apply {
-            putValueArgument(
-                0,
-                IrConstImpl.string(
-                    UNDEFINED_OFFSET,
-                    UNDEFINED_OFFSET,
-                    context.irBuiltIns.stringType,
-                    name
-                )
-            )
+    open fun throwUninitializedPropertyAccessException(builder: IrBuilderWithScope, name: String): IrExpression =
+        builder.irCall(throwErrorFunction).apply {
+            putValueArgument(0, builder.irString(name))
         }
 
     private val throwErrorFunction by lazy { context.ir.symbols.ThrowUninitializedPropertyAccessException.owner }

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

@@ -13,7 +13,11 @@ import org.jetbrains.kotlin.backend.jvm.lower.*
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.descriptors.Visibility
+import org.jetbrains.kotlin.ir.builders.IrBuilderWithScope
+import org.jetbrains.kotlin.ir.builders.irBlock
+import org.jetbrains.kotlin.ir.builders.irNull
 import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.util.PatchDeclarationParentsVisitor
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
 import org.jetbrains.kotlin.load.java.JavaVisibilities
@@ -75,7 +79,15 @@ private val expectDeclarationsRemovingPhase = makeIrModulePhase(
 )
 
 private val lateinitPhase = makeIrFilePhase(
-    ::LateinitLowering,
+    { backend: JvmBackendContext ->
+        object : LateinitLowering(backend) {
+            override fun throwUninitializedPropertyAccessException(builder: IrBuilderWithScope, name: String): IrExpression =
+                builder.irBlock {
+                    +super.throwUninitializedPropertyAccessException(builder, name)
+                    +irThrow(irNull())
+                }
+        }
+    },
     name = "Lateinit",
     description = "Insert checks for lateinit field references"
 )