[FE 1.0] Issue a warning if expect and actual are declared in the same module

The commit is based on b09561c3c3
Co-authored-by: Dmitriy Novozhilov <dmitriy.novozhilov@jetbrains.com>

^KT-40904 Fixed
^KT-55177 Fixed
Review: https://jetbrains.team/p/kt/reviews/8731

True negative test already exist:
`compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis/intermediateWithActualAndExpect.kt`

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java

@@ -22002,6 +22002,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                         KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
                     }
 
+                    @Test
+                    @TestMetadata("expectAndActualInTheSameModule.kt")
+                    public void testExpectAndActualInTheSameModule() throws Exception {
+                        runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis/expectAndActualInTheSameModule.kt");
+                    }
+
                     @Test
                     @TestMetadata("intermediateWithActualAndExpect.kt")
                     public void testIntermediateWithActualAndExpect() throws Exception {

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

@@ -22008,6 +22008,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                         KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
                     }
 
+                    @Test
+                    @TestMetadata("expectAndActualInTheSameModule.kt")
+                    public void testExpectAndActualInTheSameModule() throws Exception {
+                        runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis/expectAndActualInTheSameModule.kt");
+                    }
+
                     @Test
                     @TestMetadata("intermediateWithActualAndExpect.kt")
                     public void testIntermediateWithActualAndExpect() throws Exception {

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

@@ -22002,6 +22002,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                         KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
                     }
 
+                    @Test
+                    @TestMetadata("expectAndActualInTheSameModule.kt")
+                    public void testExpectAndActualInTheSameModule() throws Exception {
+                        runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis/expectAndActualInTheSameModule.kt");
+                    }
+
                     @Test
                     @TestMetadata("intermediateWithActualAndExpect.kt")
                     public void testIntermediateWithActualAndExpect() throws Exception {

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -804,6 +804,8 @@ public interface Errors {
             DiagnosticFactory2.create(ERROR, ACTUAL_DECLARATION_NAME);
     DiagnosticFactory0<KtNamedDeclaration> ACTUAL_MISSING = DiagnosticFactory0.create(ERROR, ACTUAL_DECLARATION_NAME);
 
+    DiagnosticFactory1<KtNamedDeclaration, MemberDescriptor> EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE = DiagnosticFactory1.create(WARNING, DECLARATION_NAME);
+
     DiagnosticFactory0<PsiElement> OPTIONAL_EXPECTATION_NOT_ON_EXPECTED = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> OPTIONAL_DECLARATION_OUTSIDE_OF_ANNOTATION_ENTRY = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> OPTIONAL_DECLARATION_USAGE_IN_NON_COMMON_SOURCE = DiagnosticFactory0.create(ERROR);

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -339,6 +339,9 @@ public class DefaultErrorMessages {
         MAP.put(NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS, "Actual class ''{0}'' has no corresponding members for expected class members:{1}",
                 NAME, adaptGenerics2(IncompatibleExpectedActualClassScopesRenderer.TEXT));
         MAP.put(ACTUAL_MISSING, "Declaration must be marked with 'actual'");
+        MAP.put(EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE,
+                "{0}: expect and corresponding actual are declared in the same module, which will be prohibited in Kotlin 2.0. See https://youtrack.jetbrains.com/issue/KT-55177",
+                CAPITALIZED_DECLARATION_NAME_WITH_KIND_AND_PLATFORM);
 
         MAP.put(OPTIONAL_EXPECTATION_NOT_ON_EXPECTED, "'@OptionalExpectation' can only be used on an expected annotation class");
         MAP.put(OPTIONAL_DECLARATION_OUTSIDE_OF_ANNOTATION_ENTRY, "Declaration annotated with '@OptionalExpectation' can only be used inside an annotation entry");

compiler/frontend/src/org/jetbrains/kotlin/resolve/PlatformConfiguratorBase.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.resolve.lazy.DelegationFilter
 import org.jetbrains.kotlin.types.DynamicTypesSettings
 
 private val DEFAULT_DECLARATION_CHECKERS = listOf(
+    ExpectActualInTheSameModuleChecker,
     DataClassDeclarationChecker(),
     ConstModifierChecker,
     UnderscoreChecker,

compiler/frontend/src/org/jetbrains/kotlin/resolve/checkers/ExpectActualInTheSameModuleChecker.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.resolve.checkers
+
+import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.descriptors.MemberDescriptor
+import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
+import org.jetbrains.kotlin.diagnostics.Errors
+import org.jetbrains.kotlin.platform.isCommon
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtNamedDeclaration
+import org.jetbrains.kotlin.resolve.descriptorUtil.module
+import org.jetbrains.kotlin.resolve.multiplatform.ExpectedActualResolver
+import org.jetbrains.kotlin.resolve.multiplatform.isCommonSource
+import org.jetbrains.kotlin.resolve.source.KotlinSourceElement
+
+object ExpectActualInTheSameModuleChecker : DeclarationChecker {
+    override fun check(declaration: KtDeclaration, descriptor: DeclarationDescriptor, context: DeclarationCheckerContext) {
+        if (!context.languageVersionSettings.supportsFeature(LanguageFeature.MultiPlatformProjects)) return
+        if (descriptor !is MemberDescriptor) return
+        if (declaration !is KtNamedDeclaration) return
+        if (!descriptor.isExpect) return
+        // Only look for top level actual members; class members will be handled as a part of that expected class
+        if (descriptor.containingDeclaration !is PackageFragmentDescriptor) return
+        val module = descriptor.module
+        val actuals = ExpectedActualResolver.findActualForExpected(descriptor, module)?.flatMap { it.value }
+            ?.takeIf(List<MemberDescriptor>::isNotEmpty) ?: return
+
+        // There are 4 cases:
+        // 1. `expect` in common module, `actual` in platform module. It's a legal situation. In K2MetadataCompiler compiler, the
+        //    declarations have different modules. In backend specific compiler, `expect` declaration is in common module so warning won't
+        //    be issued
+        // 2. `expect` in common module X, `actual` in common module Y (Y depends on X). It's a legal situation. In K2MetadataCompiler
+        //    compiler, the declarations have different modules. In backend specific compiler, `expect` declaration is in common so warning
+        //    won't be issued
+        // 3. `expect` in common module X, `actual` in the very same common module X. It's an illegal situation. In K2MetadataCompiler
+        //    compiler, the declarations have the same module, so the warning will be issue. In backend specific compiler, `expect`
+        //    declaration is in common so warning won't be issued
+        // 4. `expect` in platform module X, `actual` in the very same platform module X. It's an illegal situation. K2MetadataCompiler is
+        //    invoked only for common modules, so it won't issue a warning. In backend specific compiler, `expect` declaration is in
+        //    platform module, the warning will be issued
+        //
+        // The checker doesn't consider cases when platform module depend on another platform module.
+        if (module.platform.isCommon()) { /* If true then we are in K2MetadataCompiler. `isCommon` never returns `true` in backend specific
+                                             compilers (even when the source is truly common) */
+            // modules can be distinguished only in K2MetadataCompiler because in platform specific compiler all sources are put in
+            // a single module
+            if (actuals.all { it.module != module }) return
+        } else { // backend specific compiler
+            if (declaration.containingKtFile.isCommonSource == true) return
+        }
+
+        context.trace.report(Errors.EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE.on(declaration, descriptor))
+        for (actual in actuals) {
+            val actualSource = actual.declarationSource ?: continue
+            context.trace.report(Errors.EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE.on(actualSource, descriptor))
+        }
+    }
+
+    private val MemberDescriptor.declarationSource: KtNamedDeclaration?
+        get() = (this.source as? KotlinSourceElement)?.psi as? KtNamedDeclaration
+}

compiler/testData/compileKotlinAgainstCustomBinaries/actualTypealiasToCompiledInlineClass/expectActualLv14.kt

@@ -1,3 +1,5 @@
+@file:Suppress("EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE")
+
 package test
 
 @Suppress("INLINE_CLASS_DEPRECATED", "EXPERIMENTAL_FEATURE_WARNING")

compiler/testData/compileKotlinAgainstCustomBinaries/actualTypealiasToCompiledInlineClass/expectActualLv16.kt

@@ -1,3 +1,5 @@
+@file:Suppress("EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE")
+
 package test
 
 @kotlin.jvm.JvmInline

compiler/testData/diagnostics/tests/IncDecOperatorsInExpectClass.kt

@@ -5,9 +5,9 @@
 // SKIP_TXT
 // Issue: KT-49714
 
-expect class Counter {
+expect <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class Counter<!> {
     operator fun inc(): Counter
     operator fun dec(): Counter
 }
 
-actual typealias Counter = Int
+actual typealias <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>Counter<!> = Int

compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis/expectAndActualInTheSameModule.fir.kt

@@ -0,0 +1,64 @@
+// MODULE: common
+// TARGET_PLATFORM: Common
+expect class CommonClass {
+    fun memberFun()
+    val memberProp: Int
+    class Nested
+    inner class Inner
+}
+<!ACTUAL_WITHOUT_EXPECT!>actual class CommonClass {
+    <!ACTUAL_WITHOUT_EXPECT!>actual fun memberFun() {}<!>
+    <!ACTUAL_WITHOUT_EXPECT!>actual val memberProp: Int = 42<!>
+    <!ACTUAL_WITHOUT_EXPECT!>actual class Nested<!>
+    <!ACTUAL_WITHOUT_EXPECT!>actual inner class Inner<!>
+}<!>
+
+expect fun commonFun()
+<!ACTUAL_WITHOUT_EXPECT!>actual fun commonFun() {}<!>
+
+expect val commonProperty: String
+<!ACTUAL_WITHOUT_EXPECT!>actual val commonProperty: String
+    get() = "hello"<!>
+
+// MODULE: intermediate()()(common)
+// TARGET_PLATFORM: Common
+expect class IntermediateClass {
+    fun memberFun()
+    val memberProp: Int
+    class Nested
+    inner class Inner
+}
+<!ACTUAL_WITHOUT_EXPECT!>actual class IntermediateClass {
+    <!ACTUAL_WITHOUT_EXPECT!>actual fun memberFun() {}<!>
+    <!ACTUAL_WITHOUT_EXPECT!>actual val memberProp: Int = 42<!>
+    <!ACTUAL_WITHOUT_EXPECT!>actual class Nested<!>
+    <!ACTUAL_WITHOUT_EXPECT!>actual inner class Inner<!>
+}<!>
+
+expect fun intermediateFun()
+<!ACTUAL_WITHOUT_EXPECT!>actual fun intermediateFun() {}<!>
+
+expect val intermediateProperty: String
+<!ACTUAL_WITHOUT_EXPECT!>actual val intermediateProperty: String
+    get() = "hello"<!>
+
+// MODULE: main()()(intermediate)
+expect class PlatformClass {
+    fun memberFun()
+    val memberProp: Int
+    class Nested
+    inner class Inner
+}
+<!ACTUAL_WITHOUT_EXPECT!>actual class PlatformClass {
+    <!ACTUAL_WITHOUT_EXPECT!>actual fun memberFun() {}<!>
+    <!ACTUAL_WITHOUT_EXPECT!>actual val memberProp: Int = 42<!>
+    <!ACTUAL_WITHOUT_EXPECT!>actual class Nested<!>
+    <!ACTUAL_WITHOUT_EXPECT!>actual inner class Inner<!>
+}<!>
+
+expect fun platformFun()
+<!ACTUAL_WITHOUT_EXPECT!>actual fun platformFun() {}<!>
+
+expect val platformProperty: String
+<!ACTUAL_WITHOUT_EXPECT!>actual val platformProperty: String
+    get() = "hello"<!>

compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis/expectAndActualInTheSameModule.kt

@@ -0,0 +1,64 @@
+// MODULE: common
+// TARGET_PLATFORM: Common
+expect <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class CommonClass<!> {
+    fun memberFun()
+    val memberProp: Int
+    class Nested
+    inner class Inner
+}
+actual <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class CommonClass<!> {
+    actual fun memberFun() {}
+    actual val memberProp: Int = 42
+    actual class Nested
+    actual inner class Inner
+}
+
+expect fun <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>commonFun<!>()
+actual fun <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>commonFun<!>() {}
+
+expect val <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>commonProperty<!>: String
+actual val <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>commonProperty<!>: String
+    get() = "hello"
+
+// MODULE: intermediate()()(common)
+// TARGET_PLATFORM: Common
+expect <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class IntermediateClass<!> {
+    fun memberFun()
+    val memberProp: Int
+    class Nested
+    inner class Inner
+}
+actual <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class IntermediateClass<!> {
+    actual fun memberFun() {}
+    actual val memberProp: Int = 42
+    actual class Nested
+    actual inner class Inner
+}
+
+expect fun <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>intermediateFun<!>()
+actual fun <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>intermediateFun<!>() {}
+
+expect val <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>intermediateProperty<!>: String
+actual val <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>intermediateProperty<!>: String
+    get() = "hello"
+
+// MODULE: main()()(intermediate)
+expect <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class PlatformClass<!> {
+    fun memberFun()
+    val memberProp: Int
+    class Nested
+    inner class Inner
+}
+actual <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>class PlatformClass<!> {
+    actual fun memberFun() {}
+    actual val memberProp: Int = 42
+    actual class Nested
+    actual inner class Inner
+}
+
+expect fun <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>platformFun<!>()
+actual fun <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>platformFun<!>() {}
+
+expect val <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>platformProperty<!>: String
+actual val <!EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE!>platformProperty<!>: String
+    get() = "hello"

compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis/expectAndActualInTheSameModule.txt

@@ -0,0 +1,130 @@
+// -- Module: <common> --
+package
+
+public actual val commonProperty: kotlin.String
+public expect val commonProperty: kotlin.String
+public actual fun commonFun(): kotlin.Unit
+public expect fun commonFun(): kotlin.Unit
+
+public final actual class CommonClass {
+    public constructor CommonClass()
+    public actual final val memberProp: kotlin.Int = 42
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final actual fun memberFun(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final actual inner class Inner {
+        public constructor Inner()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final actual class Nested {
+        public constructor Nested()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final expect class CommonClass {
+    public expect final val memberProp: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final expect fun memberFun(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final expect inner class Inner {
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final expect class Nested {
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+// -- Module: <intermediate> --
+package
+
+public actual val intermediateProperty: kotlin.String
+public expect val intermediateProperty: kotlin.String
+public actual fun intermediateFun(): kotlin.Unit
+public expect fun intermediateFun(): kotlin.Unit
+
+public final actual class IntermediateClass {
+    public constructor IntermediateClass()
+    public actual final val memberProp: kotlin.Int = 42
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final actual fun memberFun(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final actual inner class Inner {
+        public constructor Inner()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final actual class Nested {
+        public constructor Nested()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public final expect class IntermediateClass {
+    public expect final val memberProp: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final expect fun memberFun(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final expect inner class Inner {
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final expect class Nested {
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+// -- Module: <main> --
+package
+
+public actual val platformProperty: kotlin.String
+public actual fun platformFun(): kotlin.Unit
+
+public final actual class PlatformClass {
+    public constructor PlatformClass()
+    public actual final val memberProp: kotlin.Int = 42
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final actual fun memberFun(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final actual inner class Inner {
+        public constructor Inner()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    public final actual class Nested {
+        public constructor Nested()
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}

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

@@ -22008,6 +22008,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                         KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
                     }
 
+                    @Test
+                    @TestMetadata("expectAndActualInTheSameModule.kt")
+                    public void testExpectAndActualInTheSameModule() throws Exception {
+                        runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/multiplatformCompositeAnalysis/expectAndActualInTheSameModule.kt");
+                    }
+
                     @Test
                     @TestMetadata("intermediateWithActualAndExpect.kt")
                     public void testIntermediateWithActualAndExpect() throws Exception {

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/frontend/classic/ClassicFrontendFacade.kt

@@ -409,8 +409,8 @@ class ClassicFrontendFacade(
         override fun registerDependencyForAllModules(moduleInfo: ModuleInfo, descriptorForModule: ModuleDescriptorImpl) = Unit
         override fun packageFragmentProviderForModuleInfo(moduleInfo: ModuleInfo): PackageFragmentProvider? = null
 
-        override val friendModuleInfos: List<ModuleInfo> get() = emptyList()
+        override val friendModuleInfos: List<ModuleInfo> = _moduleInfos.filter { it.module.shouldSeeInternalsOf(module) }
-        override val refinesModuleInfos: List<ModuleInfo> get() = emptyList()
+        override val refinesModuleInfos: List<ModuleInfo> = _moduleInfos.filter { it.module in module.allExpectedByModules }
     }
 
     @OptIn(ExperimentalStdlibApi::class)

libraries/stdlib/common/test/jsCollectionFactories.kt

@@ -2,6 +2,7 @@
  * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
+@file:Suppress("EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE")
 
 package test.collections.js
 

libraries/stdlib/common/test/testUtils.kt

@@ -2,6 +2,7 @@
  * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
+@file:Suppress("EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE")
 
 package test
 
@@ -33,4 +34,4 @@ public expect object BackReferenceHandling {
     val nonExistentGroup: HandlingOption
     val nonExistentNamedGroup: HandlingOption
     val groupZero: HandlingOption
-}
+}

libraries/stdlib/jvm/test/js/StubsJVM.kt

@@ -2,6 +2,7 @@
  * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
+@file:Suppress("EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE")
 
 package test.collections.js
 

libraries/stdlib/jvm/test/testUtilsJVM.kt

@@ -2,6 +2,7 @@
  * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
+@file:Suppress("EXPECT_AND_ACTUAL_IN_THE_SAME_MODULE")
 
 package test
 
@@ -38,4 +39,4 @@ public actual object BackReferenceHandling {
     actual val nonExistentGroup: HandlingOption = HandlingOption.MATCH_NOTHING
     actual val nonExistentNamedGroup: HandlingOption = HandlingOption.THROW
     actual val groupZero: HandlingOption = HandlingOption.THROW
-}
+}