[FIR2IR] Fix generation of val initialization after smart-cast

If neither setter nor backing field were found for an assignment call,
search overridden properties for backing fields.

^KT-57105 Fixed

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

@@ -569,7 +569,14 @@ class CallAndReferenceGenerator(
                     is IrPropertySymbol -> {
                         val irProperty = symbol.owner
                         val setter = irProperty.setter
-                        val backingField = irProperty.backingField
+                        var backingField = irProperty.backingField
+
+                        // If we found neither a setter nor a backing field, check if we have an override (possibly fake) of a val with
+                        // backing field. This can happen in a class initializer where `this` was smart-casted. See KT-57105.
+                        if (setter == null && backingField == null) {
+                            backingField = irProperty.overriddenSymbols.firstNotNullOfOrNull { it.owner.backingField }
+                        }
+
                         when {
                             setter != null -> IrCallImpl(
                                 startOffset, endOffset, type, setter.symbol,

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirLightTreeBlackBoxCodegenTestGenerated.java

@@ -48995,6 +48995,12 @@ public class FirLightTreeBlackBoxCodegenTestGenerated extends AbstractFirLightTr
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @Test
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @Test
         @TestMetadata("resolveToMemberOfSuperclass_overrideWithDifferentType.kt")
         public void testResolveToMemberOfSuperclass_overrideWithDifferentType() throws Exception {

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirPsiBlackBoxCodegenTestGenerated.java

@@ -48995,6 +48995,12 @@ public class FirPsiBlackBoxCodegenTestGenerated extends AbstractFirPsiBlackBoxCo
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @Test
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @Test
         @TestMetadata("resolveToMemberOfSuperclass_overrideWithDifferentType.kt")
         public void testResolveToMemberOfSuperclass_overrideWithDifferentType() throws Exception {

compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt

@@ -0,0 +1,16 @@
+// ISSUE: KT-57105
+
+class RootBus: MessageBusImpl()
+
+open class MessageBusImpl {
+    val parentBus: Any?
+
+    init {
+        this as RootBus
+        parentBus = "OK"
+    }
+}
+
+fun box(): String {
+    return RootBus().parentBus as String
+}

compiler/testData/ir/irText/classes/smartCastInValInitialization.fir.ir.txt

@@ -46,7 +46,10 @@ FILE fqName:<root> fileName:/smartCastInValInitialization.kt
         TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
           TYPE_OP type=<root>.RootBus origin=CAST typeOperand=<root>.RootBus
             GET_VAR '<this>: <root>.MessageBusImpl declared in <root>.MessageBusImpl' type=<root>.MessageBusImpl origin=null
-        ERROR_CALL 'Unresolved reference: R|/MessageBusImpl.parentBus|' type=IrErrorType(null)
+        SET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:parentBus type:kotlin.Any? visibility:private [final]' type=kotlin.Unit origin=null
+          receiver: TYPE_OP type=<root>.RootBus origin=IMPLICIT_CAST typeOperand=<root>.RootBus
+            GET_VAR '<this>: <root>.MessageBusImpl declared in <root>.MessageBusImpl' type=<root>.MessageBusImpl origin=null
+          value: CONST Null type=kotlin.Nothing? value=null
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any

compiler/testData/ir/irText/classes/smartCastInValInitialization.fir.kt.txt

@@ -19,7 +19,7 @@ open class MessageBusImpl {
 
   init {
     <this> as RootBus /*~> Unit */
-    error("") /* ErrorCallExpression */
+    <this> /*as RootBus */.#parentBus = null
   }
 
 }

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java

@@ -46625,6 +46625,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @Test
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @Test
         @TestMetadata("smartCastInsideIf.kt")
         public void testSmartCastInsideIf() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java

@@ -48995,6 +48995,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @Test
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @Test
         @TestMetadata("resolveToMemberOfSuperclass_overrideWithDifferentType.kt")
         public void testResolveToMemberOfSuperclass_overrideWithDifferentType() throws Exception {

compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -37743,6 +37743,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @TestMetadata("smartCastInsideIf.kt")
         public void testSmartCastInsideIf() throws Exception {
             runTest("compiler/testData/codegen/box/smartCasts/smartCastInsideIf.kt");

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/JsCodegenBoxTestGenerated.java

@@ -34573,6 +34573,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @Test
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @Test
         @TestMetadata("smartCastInsideIf.kt")
         public void testSmartCastInsideIf() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsCodegenBoxTestGenerated.java

@@ -34759,6 +34759,12 @@ public class FirJsCodegenBoxTestGenerated extends AbstractFirJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @Test
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @Test
         @TestMetadata("smartCastInsideIf.kt")
         public void testSmartCastInsideIf() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsCodegenBoxTestGenerated.java

@@ -34759,6 +34759,12 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @Test
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @Test
         @TestMetadata("smartCastInsideIf.kt")
         public void testSmartCastInsideIf() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsES6CodegenBoxTestGenerated.java

@@ -34759,6 +34759,12 @@ public class IrJsES6CodegenBoxTestGenerated extends AbstractIrJsES6CodegenBoxTes
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @Test
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @Test
         @TestMetadata("smartCastInsideIf.kt")
         public void testSmartCastInsideIf() throws Exception {

native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/K2NativeCodegenBoxTestGenerated.java

@@ -38342,6 +38342,12 @@ public class K2NativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTes
                 runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
             }
 
+            @Test
+            @TestMetadata("propertyInitializationAfterSmartCast.kt")
+            public void testPropertyInitializationAfterSmartCast() throws Exception {
+                runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+            }
+
             @Test
             @TestMetadata("smartCastInsideIf.kt")
             public void testSmartCastInsideIf() throws Exception {

native/native.tests/tests-gen/org/jetbrains/kotlin/konan/blackboxtest/NativeCodegenBoxTestGenerated.java

@@ -37862,6 +37862,12 @@ public class NativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTest
                 runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
             }
 
+            @Test
+            @TestMetadata("propertyInitializationAfterSmartCast.kt")
+            public void testPropertyInitializationAfterSmartCast() throws Exception {
+                runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+            }
+
             @Test
             @TestMetadata("smartCastInsideIf.kt")
             public void testSmartCastInsideIf() throws Exception {

wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/IrCodegenBoxWasmTestGenerated.java

@@ -31138,6 +31138,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
             runTest("compiler/testData/codegen/box/smartCasts/nullSmartCast.kt");
         }
 
+        @TestMetadata("propertyInitializationAfterSmartCast.kt")
+        public void testPropertyInitializationAfterSmartCast() throws Exception {
+            runTest("compiler/testData/codegen/box/smartCasts/propertyInitializationAfterSmartCast.kt");
+        }
+
         @TestMetadata("smartCastInsideIf.kt")
         public void testSmartCastInsideIf() throws Exception {
             runTest("compiler/testData/codegen/box/smartCasts/smartCastInsideIf.kt");