[K2, MPP] Fix reporting of MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendMPPDiagnosticsWithLightTreeTestGenerated.java

@@ -85,6 +85,12 @@ public class FirOldFrontendMPPDiagnosticsWithLightTreeTestGenerated extends Abst
         runTest("compiler/testData/diagnostics/tests/multiplatform/kt54827.kt");
     }
 
+    @Test
+    @TestMetadata("manyInterfacesMemberNotImplemented.kt")
+    public void testManyInterfacesMemberNotImplemented() throws Exception {
+        runTest("compiler/testData/diagnostics/tests/multiplatform/manyInterfacesMemberNotImplemented.kt");
+    }
+
     @Test
     @TestMetadata("modifierApplicability.kt")
     public void testModifierApplicability() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendMPPDiagnosticsWithPsiTestGenerated.java

@@ -85,6 +85,12 @@ public class FirOldFrontendMPPDiagnosticsWithPsiTestGenerated extends AbstractFi
         runTest("compiler/testData/diagnostics/tests/multiplatform/kt54827.kt");
     }
 
+    @Test
+    @TestMetadata("manyInterfacesMemberNotImplemented.kt")
+    public void testManyInterfacesMemberNotImplemented() throws Exception {
+        runTest("compiler/testData/diagnostics/tests/multiplatform/manyInterfacesMemberNotImplemented.kt");
+    }
+
     @Test
     @TestMetadata("modifierApplicability.kt")
     public void testModifierApplicability() throws Exception {

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

@@ -153,10 +153,6 @@ fun KtDiagnosticReporterWithImplicitIrBasedContext.reportMissingActual(irDeclara
     at(irDeclaration).report(CommonBackendErrors.NO_ACTUAL_FOR_EXPECT, irDeclaration.module)
 }
 
-fun KtDiagnosticReporterWithImplicitIrBasedContext.reportManyInterfacesMembersNotImplemented(declaration: IrClass, actualMember: IrDeclarationWithName) {
-    at(declaration).report(CommonBackendErrors.MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED, actualMember.name.asString())
-}
-
 internal fun IrElement.containsOptionalExpectation(): Boolean {
     return this is IrClass &&
             this.kind == ClassKind.ANNOTATION_CLASS &&

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

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.backend.common.actualizer
 
 import org.jetbrains.kotlin.KtDiagnosticReporterWithImplicitIrBasedContext
+import org.jetbrains.kotlin.backend.common.CommonBackendErrors
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.builders.declarations.buildFun
 import org.jetbrains.kotlin.ir.builders.declarations.buildProperty
@@ -39,7 +40,7 @@ class MissingFakeOverridesAdder(
 
     private fun processSupertypes(declaration: IrClass) {
         val members by lazy(LazyThreadSafetyMode.NONE) {
-            val notBuiltinMembers = declaration.declarations.filter { !it.isBuiltinMember() }
+            val notBuiltinMembers = declaration.declarations.filterNot { it.isBuiltinMember() }
             val result = mutableMapOf<String, MutableList<IrDeclaration>>()
             for (member in notBuiltinMembers) {
                 result.getOrPut(generateIrElementFullNameFromExpect(member, typeAliasMap)) { mutableListOf() }.add(member)
@@ -71,22 +72,25 @@ class MissingFakeOverridesAdder(
         }
     }
 
-    private fun addFakeOverride(actualMember: IrDeclaration, members: Map<String, List<IrDeclaration>>, declaration: IrClass) {
-        when (actualMember) {
-            is IrFunctionImpl,
-            is IrPropertyImpl -> {
-                if (members.getMatch(actualMember, expectActualMap, typeAliasMap) != null) {
-                    diagnosticsReporter.reportManyInterfacesMembersNotImplemented(declaration, actualMember as IrDeclarationWithName)
-                    return
-                }
+    private fun addFakeOverride(
+        actualMember: IrDeclaration,
+        members: MutableMap<String, MutableList<IrDeclaration>>,
+        declaration: IrClass
+    ) {
+        val newMember = when (actualMember) {
+            is IrFunctionImpl -> createFakeOverrideFunction(actualMember, declaration)
+            is IrPropertyImpl -> createFakeOverrideProperty(actualMember, declaration)
+            else -> return
+        }
 
-                val newMember = if (actualMember is IrFunctionImpl) {
-                    createFakeOverrideFunction(actualMember, declaration)
-                } else {
-                    createFakeOverrideProperty(actualMember as IrPropertyImpl, declaration)
-                }
-                declaration.declarations.add(newMember)
-            }
+        if (members.getMatch(newMember, expectActualMap, typeAliasMap) == null) {
+            declaration.declarations.add(newMember)
+            members.getOrPut(generateIrElementFullNameFromExpect(newMember, typeAliasMap)) { mutableListOf() }.add(newMember)
+        } else {
+            diagnosticsReporter.at(declaration).report(
+                CommonBackendErrors.MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED,
+                (actualMember as IrDeclarationWithName).name.asString()
+            )
         }
     }
 }

compiler/testData/diagnostics/tests/multiplatform/manyInterfacesMemberNotImplemented.fir.kt

@@ -0,0 +1,25 @@
+// TARGET_BACKEND: JVM
+// !LANGUAGE: +MultiPlatformProjects
+
+// MODULE: common
+// TARGET_PLATFORM: Common
+// FILE: common.kt
+
+expect interface S1
+expect interface S2
+
+<!MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED{JVM}!>open class A : S1, S2<!>
+
+class B : A()
+
+// MODULE: jvm()()(common)
+// TARGET_PLATFORM: JVM
+// FILE: main.kt
+
+actual interface S1 {
+    fun f() {}
+}
+
+actual interface S2 {
+    fun f() {}
+}

compiler/testData/diagnostics/tests/multiplatform/manyInterfacesMemberNotImplemented.kt

@@ -0,0 +1,25 @@
+// TARGET_BACKEND: JVM
+// !LANGUAGE: +MultiPlatformProjects
+
+// MODULE: common
+// TARGET_PLATFORM: Common
+// FILE: common.kt
+
+expect interface S1
+expect interface S2
+
+open <!MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED{JVM}!>class A<!> : S1, S2
+
+class B : A()
+
+// MODULE: jvm()()(common)
+// TARGET_PLATFORM: JVM
+// FILE: main.kt
+
+actual interface S1 {
+    fun f() {}
+}
+
+actual interface S2 {
+    fun f() {}
+}

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

@@ -21732,6 +21732,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/multiplatform/kt54827.kt");
             }
 
+            @Test
+            @TestMetadata("manyInterfacesMemberNotImplemented.kt")
+            public void testManyInterfacesMemberNotImplemented() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/multiplatform/manyInterfacesMemberNotImplemented.kt");
+            }
+
             @Test
             @TestMetadata("modifierApplicability.kt")
             public void testModifierApplicability() throws Exception {