[FIR2IR] Correctly calculate ir origin for f/o callables in declarations generator

This change uncovers one problem, which causes some MPP tests to fail
This problem will be fixed in further commits

Uncovers KT-62535

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt

@@ -686,7 +686,8 @@ fun FirSession.createFilesWithGeneratedDeclarations(): List<FirFile> {
 
 fun FirDeclaration?.computeIrOrigin(
     predefinedOrigin: IrDeclarationOrigin? = null,
-    parentOrigin: IrDeclarationOrigin? = null
+    parentOrigin: IrDeclarationOrigin? = null,
+    fakeOverrideOwnerLookupTag: ConeClassLikeLookupTag? = null
 ): IrDeclarationOrigin {
     if (this == null) {
         return predefinedOrigin ?: parentOrigin ?: IrDeclarationOrigin.DEFINED
@@ -703,6 +704,7 @@ fun FirDeclaration?.computeIrOrigin(
         }
 
         this is FirCallableDeclaration -> when {
+            fakeOverrideOwnerLookupTag != null && fakeOverrideOwnerLookupTag != containingClassLookupTag() -> IrDeclarationOrigin.FAKE_OVERRIDE
             symbol.fir.isIntersectionOverride || symbol.fir.isSubstitutionOverride -> IrDeclarationOrigin.FAKE_OVERRIDE
             parentOrigin == IrDeclarationOrigin.IR_EXTERNAL_DECLARATION_STUB && symbol.isJavaOrEnhancement -> {
                 IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/Fir2IrCallableDeclarationsGenerator.kt

@@ -105,7 +105,11 @@ class Fir2IrCallableDeclarationsGenerator(val components: Fir2IrComponents) : Fi
             // See org.jetbrains.kotlin.backend.jvm.lower.InheritedDefaultMethodsOnClassesLoweringKt.isDefinitelyNotDefaultImplsMethod
             (irParent as? IrClass)?.origin == IrDeclarationOrigin.IR_EXTERNAL_DECLARATION_STUB &&
                     function.isJavaOrEnhancement -> IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB
-            else -> function.computeIrOrigin(predefinedOrigin, parentOrigin = (irParent as? IrDeclaration)?.origin)
+            else -> function.computeIrOrigin(
+                predefinedOrigin,
+                parentOrigin = (irParent as? IrDeclaration)?.origin,
+                fakeOverrideOwnerLookupTag
+            )
         }
         val parentIsExternal = irParent.isExternalParent()
         // We don't generate signatures for local classes
@@ -268,15 +272,18 @@ class Fir2IrCallableDeclarationsGenerator(val components: Fir2IrComponents) : Fi
         isLocal: Boolean = false,
         fakeOverrideOwnerLookupTag: ConeClassLikeLookupTag? = null,
     ): IrProperty = convertCatching(property) {
-        val origin =
-            when {
-                !predefinedOrigin.isExternal &&
-                        property.isStatic &&
-                        property.name in Fir2IrDeclarationStorage.ENUM_SYNTHETIC_NAMES
-                -> IrDeclarationOrigin.ENUM_CLASS_SPECIAL_MEMBER
+        val origin = when {
+            !predefinedOrigin.isExternal &&
+                    property.isStatic &&
+                    property.name in Fir2IrDeclarationStorage.ENUM_SYNTHETIC_NAMES
+            -> IrDeclarationOrigin.ENUM_CLASS_SPECIAL_MEMBER
 
-                else -> property.computeIrOrigin(predefinedOrigin, parentOrigin = (irParent as? IrDeclaration)?.origin)
-            }
+            else -> property.computeIrOrigin(
+                predefinedOrigin,
+                parentOrigin = (irParent as? IrDeclaration)?.origin,
+                fakeOverrideOwnerLookupTag
+            )
+        }
         // See similar comments in createIrFunction above
         val parentIsExternal = irParent.isExternalParent()
         val signature =

compiler/testData/codegen/box/multiplatform/hmpp/simple.kt

@@ -5,9 +5,10 @@
 
 // WITH_STDLIB
 // !LANGUAGE: +MultiPlatformProjects
-
+// IGNORE_CODEGEN_WITH_IR_FAKE_OVERRIDE_GENERATION: KT-62535
 // TARGET_BACKEND: JVM
-
+// IGNORE_BACKEND_K2: JVM_IR
+// REASON: K2 incorrectly generates IR for B.bar f/o
 // MODULE: common
 // TARGET_PLATFORM: Common
 

compiler/testData/codegen/box/multiplatform/k2/basic/expectInterfaceInSupertypes.kt

@@ -1,6 +1,9 @@
 // IGNORE_BACKEND_K1: JS, JS_IR, JS_IR_ES6, NATIVE, WASM
 // WITH_STDLIB
 // !LANGUAGE: +MultiPlatformProjects
+// IGNORE_BACKEND_K2: JVM_IR
+// REASON: K2 incorrectly generates IR for S1.p f/o
+// IGNORE_CODEGEN_WITH_IR_FAKE_OVERRIDE_GENERATION: KT-62535
 
 // MODULE: common
 // TARGET_PLATFORM: Common
@@ -41,4 +44,4 @@ fun box(): String {
     } else {
         "FAIL"
     }
-}
+}

compiler/testData/codegen/box/multiplatform/k2/basic/expectInterfaceInSupertypes2.kt

@@ -1,6 +1,9 @@
 // IGNORE_BACKEND_K1: JS, JS_IR, JS_IR_ES6, NATIVE, WASM
 // WITH_STDLIB
+// IGNORE_CODEGEN_WITH_IR_FAKE_OVERRIDE_GENERATION: KT-62535
 // !LANGUAGE: +MultiPlatformProjects
+// IGNORE_BACKEND_K2: ANY
+// REASON: K2 incorrectly generates IR for S2.s3 f/o
 
 // MODULE: common
 // TARGET_PLATFORM: Common
@@ -39,4 +42,4 @@ actual interface S : S1, S2 {
     fun s3() = s1() + s2()
 }
 
-fun box() = B().s3()
+fun box() = B().s3()