[K/N][IR] Generate missing return statement, p. 2

^KT-42832

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/ReturnsInsertionLowering.kt

@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.ir.declarations.IrFile
 import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.IrBlockBodyImpl
+import org.jetbrains.kotlin.ir.util.isSimpleTypeWithQuestionMark
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid
@@ -42,10 +43,11 @@ internal class ReturnsInsertionLowering(val context: Context) : FileLoweringPass
                         is IrBlockBody -> {
                             if (declaration is IrConstructor || declaration.returnType == context.irBuiltIns.unitType) {
                                 body.statements += irReturn(irGetObject(symbols.unit))
-                            } else if (declaration.returnType == context.irBuiltIns.nothingNType) {
-                                val typeOperatorCall = body.statements.singleOrNull() as? IrTypeOperatorCall
+                            } else if (declaration.returnType.isSimpleTypeWithQuestionMark) {
+                                // this is a workaround for KT-42832
+                                val typeOperatorCall = body.statements.lastOrNull() as? IrTypeOperatorCall
                                 if (typeOperatorCall?.operator == IrTypeOperator.IMPLICIT_COERCION_TO_UNIT) {
-                                    body.statements[0] = irReturn(typeOperatorCall.argument)
+                                    body.statements[body.statements.lastIndex] = irReturn(typeOperatorCall.argument)
                                 }
                             }
                         }

kotlin-native/backend.native/tests/build.gradle

@@ -528,14 +528,9 @@ task sum_3const(type: KonanLocalTest) {
     source = "codegen/function/sum_3const.kt"
 }
 
-standaloneTest("function_nothingN_returning_safe_call1") {
-    flags = ["-g", "-entry", "codegen.function.nothingN_returning_safe_call1.main"]
-    source = "codegen/function/nothingNReturningSafeCall1.kt"
-}
-
-standaloneTest("function_nothingN_returning_safe_call2") {
-    flags = ["-g", "-entry", "codegen.function.nothingN_returning_safe_call2.main"]
-    source = "codegen/function/nothingNReturningSafeCall2.kt"
+standaloneTest("function_nothingN_returning_safe_call") {
+    flags = ["-g", "-entry", "codegen.function.nothingN_returning_safe_call.main"]
+    source = "codegen/function/nothingNReturningSafeCall.kt"
 }
 
 task codegen_controlflow_for_loops(type: KonanLocalTest) {

kotlin-native/backend.native/tests/codegen/function/nothingNReturningSafeCall.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package codegen.function.nothingN_returning_safe_call
+
+import kotlin.test.*
+
+fun Any.nothing(): Nothing {
+    while (true) {}
+}
+
+class Anything
+
+fun testFunction1(obj: Any?): Nothing? = obj?.nothing()
+fun testFunction2(obj: Any?): Any? = obj?.nothing()
+fun testFunction3(obj: Any?): String? = obj?.nothing()
+fun testFunction4(obj: Any?): Unit? = obj?.nothing()
+fun testFunction5(obj: Any?): Anything? = obj?.nothing()
+
+fun testLambda1() {
+    val block: (Any?) -> Nothing? = {
+        it?.nothing()
+    }
+    block(null)
+}
+
+fun testLambda2() {
+    val block: (Any?) -> Nothing? = {
+        println() // more than one statement inside of the body
+        it?.nothing()
+    }
+    block(null)
+}
+
+fun main() {
+    testFunction1(null)
+    testFunction2(null)
+    testFunction3(null)
+    testFunction4(null)
+    testFunction5(null)
+
+    testLambda1()
+    testLambda2()
+}

kotlin-native/backend.native/tests/codegen/function/nothingNReturningSafeCall1.kt

@@ -1,18 +0,0 @@
-/*
- * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package codegen.function.nothingN_returning_safe_call1
-
-import kotlin.test.*
-
-fun Any.nothing(): Nothing {
-    while (true) {}
-}
-
-fun foo(obj: Any?): Nothing? = obj?.nothing()
-
-fun main() {
-    foo(null)
-}

kotlin-native/backend.native/tests/codegen/function/nothingNReturningSafeCall2.kt

@@ -1,23 +0,0 @@
-/*
- * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package codegen.function.nothingN_returning_safe_call2
-
-import kotlin.test.*
-
-fun Any.nothing(): Nothing {
-    while (true) {}
-}
-
-fun foo() {
-    val block: (Any?) -> Nothing? = {
-        it?.nothing()
-    }
-    block(null)
-}
-
-fun main() {
-    foo()
-}