[FIR2IR] Treat delegated functions as fake-overrides

Delegated callables in FIR are session-dependant (as fake-overrides),
  so it's incorrect to use their FIR as a key for declaration storage.
  Pair of original function and owner lookup tag should be used instead

^KT-62671 Fixed

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt

@@ -13,7 +13,6 @@ import org.jetbrains.kotlin.fir.*
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.builder.buildProperty
 import org.jetbrains.kotlin.fir.declarations.synthetic.FirSyntheticProperty
-import org.jetbrains.kotlin.fir.declarations.utils.isExpect
 import org.jetbrains.kotlin.fir.declarations.utils.isStatic
 import org.jetbrains.kotlin.fir.declarations.utils.nameOrSpecialName
 import org.jetbrains.kotlin.fir.declarations.utils.visibility
@@ -36,11 +35,12 @@ import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.declarations.UNDEFINED_PARAMETER_INDEX
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.declarations.impl.IrClassImpl
-import org.jetbrains.kotlin.ir.declarations.lazy.IrLazyClass
 import org.jetbrains.kotlin.ir.expressions.IrSyntheticBodyKind
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.symbols.impl.IrClassSymbolImpl
-import org.jetbrains.kotlin.ir.util.*
+import org.jetbrains.kotlin.ir.util.IdSignature
+import org.jetbrains.kotlin.ir.util.classId
+import org.jetbrains.kotlin.ir.util.createParameterDeclarations
 import org.jetbrains.kotlin.load.kotlin.FacadeClassSource
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -321,7 +321,7 @@ class Fir2IrDeclarationStorage(
             }
 
             function.isFakeOverride(fakeOverrideOwnerLookupTag) -> {
-                val originalFunction = function.unwrapFakeOverrides()
+                val originalFunction = function.unwrapFakeOverridesOrDelegated()
                 val key = FakeOverrideIdentifier(
                     originalFunction.symbol,
                     fakeOverrideOwnerLookupTag ?: function.containingClassLookupTag()!!
@@ -516,7 +516,7 @@ class Fir2IrDeclarationStorage(
             setterForPropertyCache[irPropertySymbol] = it.symbol
         }
         if (property.isFakeOverride(fakeOverrideOwnerLookupTag)) {
-            val originalProperty = property.unwrapFakeOverrides()
+            val originalProperty = property.unwrapFakeOverridesOrDelegated()
             val key = FakeOverrideIdentifier(
                 originalProperty.symbol,
                 fakeOverrideOwnerLookupTag ?: property.containingClassLookupTag()!!
@@ -1155,7 +1155,7 @@ class Fir2IrDeclarationStorage(
 }
 
 internal fun FirCallableDeclaration.isFakeOverride(fakeOverrideOwnerLookupTag: ConeClassLikeLookupTag?): Boolean {
-    if (isSubstitutionOrIntersectionOverride) return true
+    if (isCopyCreatedInScope) return true
     if (fakeOverrideOwnerLookupTag == null) return false
     // this condition is true for all places when we are trying to create "fake" fake overrides in IR
     // "fake" fake overrides are f/o which are presented in IR but have no corresponding FIR f/o

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

@@ -34521,6 +34521,12 @@ public class FirLightTreeBlackBoxCodegenTestGenerated extends AbstractFirLightTr
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

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

@@ -34521,6 +34521,12 @@ public class FirLightTreeBlackBoxCodegenWithIrFakeOverrideGeneratorTestGenerated
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

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

@@ -34521,6 +34521,12 @@ public class FirPsiBlackBoxCodegenTestGenerated extends AbstractFirPsiBlackBoxCo
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt

@@ -0,0 +1,24 @@
+// IGNORE_BACKEND_K1: JS, JS_IR, JS_IR_ES6, NATIVE, WASM
+// LANGUAGE: +MultiPlatformProjects
+// ISSUE: KT-62671
+
+// MODULE: common
+// FILE: common.kt
+interface A {
+    fun foo(x: Int = 1): String
+}
+
+class B : A  {
+    override fun foo(x: Int): String {
+        return if (x == 1) "OK" else "Fail: $x"
+    }
+}
+
+class X(val delegate: A = B()) : A by delegate
+
+// MODULE: platform()()(common)
+// FILE: platform.kt
+fun box(): String {
+    val x = X()
+    return x.foo()
+}

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

@@ -32757,6 +32757,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

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

@@ -34521,6 +34521,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

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

@@ -34521,6 +34521,12 @@ public class IrBlackBoxCodegenWithIrInlinerTestGenerated extends AbstractIrBlack
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

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

@@ -29532,6 +29532,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/annotations.kt");
                 }
 
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @TestMetadata("expectPropertyAsDefaultArgument.kt")
                 public void testExpectPropertyAsDefaultArgument() throws Exception {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/expectPropertyAsDefaultArgument.kt");

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

@@ -24147,6 +24147,12 @@ public class FirJsCodegenBoxTestGenerated extends AbstractFirJsCodegenBoxTest {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsES6CodegenBoxTestGenerated.java

@@ -24147,6 +24147,12 @@ public class FirJsES6CodegenBoxTestGenerated extends AbstractFirJsES6CodegenBoxT
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

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

@@ -24147,6 +24147,12 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

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

@@ -24147,6 +24147,12 @@ public class IrJsES6CodegenBoxTestGenerated extends AbstractIrJsES6CodegenBoxTes
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

native/native.tests/tests-gen/org/jetbrains/kotlin/konan/test/blackbox/FirNativeCodegenBoxTestGenerated.java

@@ -27134,6 +27134,12 @@ public class FirNativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTe
                         runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                     }
 
+                    @Test
+                    @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                    public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                        runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                    }
+
                     @Test
                     @TestMetadata("delegatedExpectedInterface.kt")
                     public void testDelegatedExpectedInterface() throws Exception {

native/native.tests/tests-gen/org/jetbrains/kotlin/konan/test/blackbox/FirNativeCodegenBoxTestNoPLGenerated.java

@@ -27758,6 +27758,12 @@ public class FirNativeCodegenBoxTestNoPLGenerated extends AbstractNativeCodegenB
                         runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                     }
 
+                    @Test
+                    @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                    public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                        runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                    }
+
                     @Test
                     @TestMetadata("delegatedExpectedInterface.kt")
                     public void testDelegatedExpectedInterface() throws Exception {

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

@@ -26823,6 +26823,12 @@ public class NativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTest
                         runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                     }
 
+                    @Test
+                    @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                    public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                        runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                    }
+
                     @Test
                     @TestMetadata("delegatedExpectedInterface.kt")
                     public void testDelegatedExpectedInterface() throws Exception {

native/native.tests/tests-gen/org/jetbrains/kotlin/konan/test/blackbox/NativeCodegenBoxTestNoPLGenerated.java

@@ -27135,6 +27135,12 @@ public class NativeCodegenBoxTestNoPLGenerated extends AbstractNativeCodegenBoxT
                         runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                     }
 
+                    @Test
+                    @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                    public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                        runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                    }
+
                     @Test
                     @TestMetadata("delegatedExpectedInterface.kt")
                     public void testDelegatedExpectedInterface() throws Exception {

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

@@ -23895,6 +23895,12 @@ public class FirWasmCodegenBoxTestGenerated extends AbstractFirWasmCodegenBoxTes
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {

wasm/wasm.tests/tests-gen/org/jetbrains/kotlin/wasm/test/K1WasmCodegenBoxTestGenerated.java

@@ -23895,6 +23895,12 @@ public class K1WasmCodegenBoxTestGenerated extends AbstractK1WasmCodegenBoxTest
                     runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/constructor.kt");
                 }
 
+                @Test
+                @TestMetadata("defaultArgumentInDelegatedFunction.kt")
+                public void testDefaultArgumentInDelegatedFunction() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/defaultArguments/defaultArgumentInDelegatedFunction.kt");
+                }
+
                 @Test
                 @TestMetadata("delegatedExpectedInterface.kt")
                 public void testDelegatedExpectedInterface() throws Exception {