[FIR2IR] Don't add synthetic propertiy fake overrides to parent class

This fixes a KMP issue where IrActualizer would add duplicate
fake overrides because the parent class would have both the getter
and the synthetic property in its list of declarations.
Now, the synthetic property fake overrides are still generated and
cached in the Fir2IrDeclarationStorage, but not added to the class.

#KT-60854 Fixed

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

@@ -99,7 +99,10 @@ class FakeOverrideGenerator(
         if (none { it is IrProperty }) {
             FirSyntheticPropertiesScope.createIfSyntheticNamesProviderIsDefined(session, firClass.defaultType(), useSiteMemberScope)?.let {
                 generateFakeOverridesForName(
-                    irClass, it, name, firClass, this,
+                    irClass, it, name, firClass,
+                    // We pass result = null so that the IR declaration is not added to the class' list of declarations
+                    // but is still cached in the declaration storage.
+                    result = null,
                     // This parameter is only needed for data-class methods that is irrelevant for lazy library classes
                     realDeclarationSymbols = emptySet()
                 )
@@ -120,7 +123,7 @@ class FakeOverrideGenerator(
         useSiteOrStaticScope: FirScope,
         name: Name,
         firClass: FirClass,
-        result: MutableList<IrDeclaration>,
+        result: MutableList<IrDeclaration>?,
         realDeclarationSymbols: Set<FirBasedSymbol<*>>
     ) {
         val isLocal = firClass !is FirRegularClass || firClass.isLocal
@@ -239,7 +242,7 @@ class FakeOverrideGenerator(
         createIrDeclaration: (firDeclaration: D, irParent: IrClass, thisReceiverOwner: IrClass?, origin: IrDeclarationOrigin, isLocal: Boolean) -> I,
         createFakeOverrideSymbol: (firDeclaration: D, baseSymbol: S) -> S,
         baseSymbols: MutableMap<I, List<S>>,
-        result: MutableList<in I>,
+        result: MutableList<in I>?,
         containsErrorTypes: (I) -> Boolean,
         realDeclarationSymbols: Set<FirBasedSymbol<*>>,
         computeDirectOverridden: FirTypeScope.(S) -> List<S>,
@@ -295,7 +298,8 @@ class FakeOverrideGenerator(
             return
         }
         baseSymbols[irDeclaration] = baseFirSymbolsForFakeOverride
-        result += irDeclaration
+
+        result?.add(irDeclaration)
     }
 
     private inline fun <D : FirCallableDeclaration, reified S : FirCallableSymbol<D>> createFirFakeOverride(

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

@@ -33429,6 +33429,12 @@ public class FirLightTreeBlackBoxCodegenTestGenerated extends AbstractFirLightTr
             runTest("compiler/testData/codegen/box/multiplatform/kt59613.kt");
         }
 
+        @Test
+        @TestMetadata("kt60854.kt")
+        public void testKt60854() throws Exception {
+            runTest("compiler/testData/codegen/box/multiplatform/kt60854.kt");
+        }
+
         @Test
         @TestMetadata("noArgActualConstructor.kt")
         public void testNoArgActualConstructor() throws Exception {

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

@@ -33429,6 +33429,12 @@ public class FirPsiBlackBoxCodegenTestGenerated extends AbstractFirPsiBlackBoxCo
             runTest("compiler/testData/codegen/box/multiplatform/kt59613.kt");
         }
 
+        @Test
+        @TestMetadata("kt60854.kt")
+        public void testKt60854() throws Exception {
+            runTest("compiler/testData/codegen/box/multiplatform/kt60854.kt");
+        }
+
         @Test
         @TestMetadata("noArgActualConstructor.kt")
         public void testNoArgActualConstructor() throws Exception {

compiler/testData/codegen/box/multiplatform/kt60854.kt

@@ -0,0 +1,20 @@
+// LANGUAGE: +MultiPlatformProjects
+// TARGET_BACKEND: JVM_IR
+// IGNORE_BACKEND_K1: ANY
+// ISSUE: KT-60854
+// WITH_STDLIB
+// FULL_JDK
+
+// MODULE: common
+// FILE: common.kt
+
+expect open class CancellationException(message: String?) : IllegalStateException
+
+class TimeoutCancellationException(message: String) : CancellationException(message)
+
+// MODULE: platform()()(common)
+// FILE: platform.kt
+
+public actual typealias CancellationException = java.util.concurrent.CancellationException
+
+fun box(): String = "OK"

compiler/testData/ir/irText/classes/kt45853.__AX.fir.ir.txt

@@ -15,16 +15,6 @@ CLASS IR_EXTERNAL_JAVA_DECLARATION_STUB CLASS name:AX modality:ABSTRACT visibili
     overridden:
       public abstract fun getA (): @[FlexibleNullability] <root>.X? declared in <root>.X
     $this: VALUE_PARAMETER FAKE_OVERRIDE name:<this> type:<root>.AX
-  PROPERTY IR_EXTERNAL_JAVA_DECLARATION_STUB name:a visibility:public modality:OPEN [val]
-    overridden:
-      public abstract a: <root>.A? [val]
-    FUN IR_EXTERNAL_JAVA_DECLARATION_STUB name:<get-a> visibility:public modality:OPEN <> ($this:<root>.AX) returnType:@[FlexibleNullability] <root>.AX?
-      annotations:
-        Override
-      correspondingProperty: PROPERTY IR_EXTERNAL_JAVA_DECLARATION_STUB name:a visibility:public modality:OPEN [val]
-      overridden:
-        public abstract fun <get-a> (): <root>.A? declared in <root>.A
-      $this: VALUE_PARAMETER IR_EXTERNAL_JAVA_DECLARATION_STUB name:<this> type:<root>.AX
   FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:<root>.AX, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
     overridden:
       public open fun equals (other: kotlin.Any?): kotlin.Boolean [fake_override,operator] declared in <root>.A

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

@@ -33429,6 +33429,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/multiplatform/kt59613.kt");
         }
 
+        @Test
+        @TestMetadata("kt60854.kt")
+        public void testKt60854() throws Exception {
+            runTest("compiler/testData/codegen/box/multiplatform/kt60854.kt");
+        }
+
         @Test
         @TestMetadata("noArgActualConstructor.kt")
         public void testNoArgActualConstructor() throws Exception {

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

@@ -33429,6 +33429,12 @@ public class IrBlackBoxCodegenWithIrInlinerTestGenerated extends AbstractIrBlack
             runTest("compiler/testData/codegen/box/multiplatform/kt59613.kt");
         }
 
+        @Test
+        @TestMetadata("kt60854.kt")
+        public void testKt60854() throws Exception {
+            runTest("compiler/testData/codegen/box/multiplatform/kt60854.kt");
+        }
+
         @Test
         @TestMetadata("noArgActualConstructor.kt")
         public void testNoArgActualConstructor() throws Exception {

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

@@ -28466,6 +28466,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/multiplatform/kt59613.kt");
         }
 
+        @TestMetadata("kt60854.kt")
+        public void testKt60854() throws Exception {
+            runTest("compiler/testData/codegen/box/multiplatform/kt60854.kt");
+        }
+
         @TestMetadata("noArgActualConstructor.kt")
         public void testNoArgActualConstructor() throws Exception {
             runTest("compiler/testData/codegen/box/multiplatform/noArgActualConstructor.kt");