[K2, MPP] Fix actualization of nullability-based overloads

^KT-58043 Fixed

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

@@ -33467,6 +33467,12 @@ public class FirLightTreeBlackBoxCodegenTestGenerated extends AbstractFirLightTr
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @Test
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @Test
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {

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

@@ -33467,6 +33467,12 @@ public class FirPsiBlackBoxCodegenTestGenerated extends AbstractFirPsiBlackBoxCo
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @Test
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @Test
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/actualizer/IrActualizerUtils.kt

@@ -15,12 +15,16 @@ import org.jetbrains.kotlin.ir.symbols.IrSymbol
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
 import org.jetbrains.kotlin.ir.types.IrDynamicType
 import org.jetbrains.kotlin.ir.types.classifierOrFail
+import org.jetbrains.kotlin.ir.types.isNullable
 import org.jetbrains.kotlin.ir.util.hasAnnotation
 import org.jetbrains.kotlin.ir.util.kotlinFqName
 import org.jetbrains.kotlin.ir.util.module
 import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.resolve.multiplatform.OptionalAnnotationUtil
 
+private val FLEXIBLE_NULLABILITY_ANNOTATION_FQ_NAME = StandardClassIds.Annotations.FlexibleNullability.asSingleFqName()
+
 internal fun Map<String, List<IrDeclaration>>.getMatches(
     expectDeclaration: IrDeclaration,
     expectActualTypesMap: Map<IrSymbol, IrSymbol>,
@@ -44,7 +48,7 @@ private inline fun List<IrDeclaration>.getMatches(
 }
 
 private fun IrFunction.match(actualFunction: IrFunction, expectActualTypesMap: Map<IrSymbol, IrSymbol>): Boolean {
-    fun getActualizedValueParameterSymbol(
+    fun getActualizedTypeClassifierSymbol(
         expectParameter: IrValueParameter,
         localTypeParametersMap: Map<IrTypeParameterSymbol, IrTypeParameterSymbol>? = null
     ): IrSymbol {
@@ -74,8 +78,15 @@ private fun IrFunction.match(actualFunction: IrFunction, expectActualTypesMap: M
             return true
         }
 
-        if (getActualizedValueParameterSymbol(expectParameter, localTypeParametersMap) !=
+        if (expectParameter.type.isNullable() != actualParameter.type.isNullable() &&
-            getActualizedValueParameterSymbol(actualParameter)
+            !expectParameter.type.annotations.hasAnnotation(FLEXIBLE_NULLABILITY_ANNOTATION_FQ_NAME) &&
+            !actualParameter.type.annotations.hasAnnotation(FLEXIBLE_NULLABILITY_ANNOTATION_FQ_NAME)
+        ) {
+            return false
+        }
+
+        if (getActualizedTypeClassifierSymbol(expectParameter, localTypeParametersMap) !=
+            getActualizedTypeClassifierSymbol(actualParameter)
         ) {
             return false
         }

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

@@ -0,0 +1,20 @@
+// IGNORE_BACKEND: JVM, JVM_IR
+// IGNORE_BACKEND_K1: JS, JS_IR, JS_IR_ES6, NATIVE
+// !LANGUAGE: +MultiPlatformProjects
+
+// MODULE: common
+// FILE: common.kt
+
+expect fun o(x: String?): String?
+expect fun k(x: String?): String?
+
+fun box() = o(null) + k(null)
+
+// MODULE: platform()()(common)
+// FILE: platform.kt
+
+fun o(x: String) = ""
+actual fun o(x: String?): String? = "O"
+
+actual fun k(x: String?): String? = "K"
+fun k(x: String) = ""

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

@@ -32027,6 +32027,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @Test
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @Test
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {

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

@@ -33467,6 +33467,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @Test
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @Test
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {

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

@@ -33467,6 +33467,12 @@ public class IrBlackBoxCodegenWithIrInlinerTestGenerated extends AbstractIrBlack
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @Test
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @Test
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {

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

@@ -27225,6 +27225,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             @TestDataPath("$PROJECT_ROOT")
             @RunWith(JUnit3RunnerWithInners.class)
             public static class Basic extends AbstractLightAnalysisModeTest {
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void ignoreExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @TestMetadata("expectProperty.kt")
                 public void ignoreExpectProperty() throws Exception {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectProperty.kt");

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

@@ -23245,6 +23245,12 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @Test
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @Test
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {

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

@@ -23383,6 +23383,12 @@ public class FirJsCodegenBoxTestGenerated extends AbstractFirJsCodegenBoxTest {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @Test
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @Test
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {

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

@@ -23383,6 +23383,12 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @Test
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @Test
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {

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

@@ -23383,6 +23383,12 @@ public class IrJsES6CodegenBoxTestGenerated extends AbstractIrJsES6CodegenBoxTes
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @Test
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @Test
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {

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

@@ -26809,6 +26809,12 @@ public class FirNativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTe
                         runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                     }
 
+                    @Test
+                    @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                    public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                        runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                    }
+
                     @Test
                     @TestMetadata("expectActualOverloads.kt")
                     public void testExpectActualOverloads() throws Exception {

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

@@ -27419,6 +27419,12 @@ public class FirNativeCodegenBoxTestNoPLGenerated extends AbstractNativeCodegenB
                         runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                     }
 
+                    @Test
+                    @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                    public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                        runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                    }
+
                     @Test
                     @TestMetadata("expectActualOverloads.kt")
                     public void testExpectActualOverloads() throws Exception {

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

@@ -26504,6 +26504,12 @@ public class NativeCodegenBoxTestGenerated extends AbstractNativeCodegenBoxTest
                         runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                     }
 
+                    @Test
+                    @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                    public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                        runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                    }
+
                     @Test
                     @TestMetadata("expectActualOverloads.kt")
                     public void testExpectActualOverloads() throws Exception {

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

@@ -27114,6 +27114,12 @@ public class NativeCodegenBoxTestNoPLGenerated extends AbstractNativeCodegenBoxT
                         runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                     }
 
+                    @Test
+                    @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                    public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                        runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                    }
+
                     @Test
                     @TestMetadata("expectActualOverloads.kt")
                     public void testExpectActualOverloads() throws Exception {

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

@@ -20811,6 +20811,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualMultiCommon.kt");
                 }
 
+                @TestMetadata("expectActualNullabilityBasedOverloads.kt")
+                public void testExpectActualNullabilityBasedOverloads() throws Exception {
+                    runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualNullabilityBasedOverloads.kt");
+                }
+
                 @TestMetadata("expectActualOverloads.kt")
                 public void testExpectActualOverloads() throws Exception {
                     runTest("compiler/testData/codegen/box/multiplatform/k2/basic/expectActualOverloads.kt");