[FIR] KT-55570 Fix ACTUAL_WITHOUT_EXPECT reporting for empty classes

- FirExpectActualMatcherTransformer: Instead of returning,
  `transformMemberDeclaration` must assign an empty map to
  `expectForActualData` so that `FirExpectActualDeclarationChecker`
  doesn't assume that the member declaration needs no expect-actual
  checking.

^KT-55570 fixed

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

@@ -21827,6 +21827,18 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                     KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/multiplatform/hmpp"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
                 }
 
+                @Test
+                @TestMetadata("intermediateWithActualAndExpect.kt")
+                public void testIntermediateWithActualAndExpect() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/intermediateWithActualAndExpect.kt");
+                }
+
+                @Test
+                @TestMetadata("kt-55570.kt")
+                public void testKt_55570() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/kt-55570.kt");
+                }
+
                 @Test
                 @TestMetadata("sealedInheritorsInComplexModuleStructure.kt")
                 public void testSealedInheritorsInComplexModuleStructure() throws Exception {

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

@@ -21833,6 +21833,18 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                     KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/multiplatform/hmpp"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
                 }
 
+                @Test
+                @TestMetadata("intermediateWithActualAndExpect.kt")
+                public void testIntermediateWithActualAndExpect() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/intermediateWithActualAndExpect.kt");
+                }
+
+                @Test
+                @TestMetadata("kt-55570.kt")
+                public void testKt_55570() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/kt-55570.kt");
+                }
+
                 @Test
                 @TestMetadata("sealedInheritorsInComplexModuleStructure.kt")
                 public void testSealedInheritorsInComplexModuleStructure() throws Exception {

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

@@ -21827,6 +21827,18 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                     KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/multiplatform/hmpp"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
                 }
 
+                @Test
+                @TestMetadata("intermediateWithActualAndExpect.kt")
+                public void testIntermediateWithActualAndExpect() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/intermediateWithActualAndExpect.kt");
+                }
+
+                @Test
+                @TestMetadata("kt-55570.kt")
+                public void testKt_55570() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/kt-55570.kt");
+                }
+
                 @Test
                 @TestMetadata("sealedInheritorsInComplexModuleStructure.kt")
                 public void testSealedInheritorsInComplexModuleStructure() throws Exception {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/mpp/FirExpectActualMatcherTransformer.kt

@@ -79,11 +79,15 @@ open class FirExpectActualMatcherTransformer(
     private fun transformMemberDeclaration(memberDeclaration: FirMemberDeclaration) {
         if (!memberDeclaration.isActual) return
         val actualSymbol = memberDeclaration.symbol
+
+        // Regardless of whether any `expect` symbols are found for `memberDeclaration`, it must be assigned an `expectForActual` map.
+        // Otherwise, `FirExpectActualDeclarationChecker` will assume that the symbol needs no checking and not report an
+        // `EXPECT_WITHOUT_ACTUAL` error.
         val expectForActualData = FirExpectActualResolver.findExpectForActual(
             actualSymbol,
             session,
             scopeSession
-        ) ?: return
+        ) ?: mapOf()
         memberDeclaration.expectForActual = expectForActualData
         for ((compatibility, expectSymbols) in expectForActualData) {
             if (compatibility.compatible) {

compiler/testData/diagnostics/tests/multiplatform/hmpp/intermediateWithActualAndExpect.kt

@@ -0,0 +1,15 @@
+// FIR_IDENTICAL
+
+// MODULE: common
+// TARGET_PLATFORM: Common
+expect class A
+expect class B
+
+// MODULE: intermediate()()(common)
+// TARGET_PLATFORM: Common
+actual class B
+expect class C
+
+// MODULE: main()()(intermediate)
+actual class A
+actual class C

compiler/testData/diagnostics/tests/multiplatform/hmpp/intermediateWithActualAndExpect.txt

@@ -0,0 +1,66 @@
+// -- Module: <common> --
+package
+
+public final expect class A {
+    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 B {
+    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 final expect class A {
+    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 B {
+    public constructor B()
+    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 B {
+    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 C {
+    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 final actual class A {
+    public constructor A()
+    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 B {
+    public constructor B()
+    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 C {
+    public constructor C()
+    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/testData/diagnostics/tests/multiplatform/hmpp/kt-55570.fir.kt

@@ -0,0 +1,5 @@
+// MODULE: common
+// TARGET_PLATFORM: Common
+
+// MODULE: main()()(common)
+<!ACTUAL_WITHOUT_EXPECT!>actual class A<!>

compiler/testData/diagnostics/tests/multiplatform/hmpp/kt-55570.kt

@@ -0,0 +1,5 @@
+// MODULE: common
+// TARGET_PLATFORM: Common
+
+// MODULE: main()()(common)
+actual class <!ACTUAL_WITHOUT_EXPECT!>A<!>

compiler/testData/diagnostics/tests/multiplatform/hmpp/kt-55570.txt

@@ -0,0 +1,13 @@
+// -- Module: <common> --
+package
+
+
+// -- Module: <main> --
+package
+
+public final actual class A {
+    public constructor A()
+    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/testData/diagnostics/tests/multiplatform/hmpp/simple.kt

@@ -1,13 +1,5 @@
 // FIR_IDENTICAL
 // FIR_IDE_IGNORE
-/*
- * This test is used for general testing of how compiler diagnostics tests for HMPP projects works
- * Js backend is ignored because they use old test infrastructure which doesn't support HMPP
- */
-
-
-// IGNORE_BACKEND_K2: JVM_IR
-// TARGET_BACKEND: JVM
 
 // MODULE: common
 // TARGET_PLATFORM: Common

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

@@ -1,12 +1,12 @@
 
-<!DEPRECATED_MODIFIER, INCOMPATIBLE_MODIFIERS!>header<!> <!INCOMPATIBLE_MODIFIERS!>impl<!> class First
+<!ACTUAL_WITHOUT_EXPECT!><!DEPRECATED_MODIFIER, INCOMPATIBLE_MODIFIERS!>header<!> <!INCOMPATIBLE_MODIFIERS!>impl<!> class First<!>
 
 <!DEPRECATED_MODIFIER, INCOMPATIBLE_MODIFIERS!>header<!> <!INCOMPATIBLE_MODIFIERS!>expect<!> class Second
 
-<!DEPRECATED_MODIFIER, INCOMPATIBLE_MODIFIERS!>header<!> <!INCOMPATIBLE_MODIFIERS!>actual<!> class Third
+<!ACTUAL_WITHOUT_EXPECT!><!DEPRECATED_MODIFIER, INCOMPATIBLE_MODIFIERS!>header<!> <!INCOMPATIBLE_MODIFIERS!>actual<!> class Third<!>
 
-<!DEPRECATED_MODIFIER, INCOMPATIBLE_MODIFIERS!>impl<!> <!INCOMPATIBLE_MODIFIERS!>expect<!> class Fourth
+<!ACTUAL_WITHOUT_EXPECT!><!DEPRECATED_MODIFIER, INCOMPATIBLE_MODIFIERS!>impl<!> <!INCOMPATIBLE_MODIFIERS!>expect<!> class Fourth<!>
 
-<!DEPRECATED_MODIFIER, INCOMPATIBLE_MODIFIERS!>impl<!> <!INCOMPATIBLE_MODIFIERS!>actual<!> class Fifth
+<!ACTUAL_WITHOUT_EXPECT!><!DEPRECATED_MODIFIER, INCOMPATIBLE_MODIFIERS!>impl<!> <!INCOMPATIBLE_MODIFIERS!>actual<!> class Fifth<!>
 
-<!INCOMPATIBLE_MODIFIERS!>expect<!> <!INCOMPATIBLE_MODIFIERS!>actual<!> class Sixth
+<!ACTUAL_WITHOUT_EXPECT!><!INCOMPATIBLE_MODIFIERS!>expect<!> <!INCOMPATIBLE_MODIFIERS!>actual<!> class Sixth<!>

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

@@ -22,7 +22,7 @@ fun foo() {
 // FILE: jvm.kt
 
 class Outer <!ACTUAL_WITHOUT_EXPECT!>actual constructor()<!> {
-    actual class Nested
+    <!ACTUAL_WITHOUT_EXPECT!>actual class Nested<!>
 
     <!WRONG_MODIFIER_TARGET!>actual<!> init {}
 }

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

@@ -21833,6 +21833,18 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/multiplatform/hmpp"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.(fir|ll)\\.kts?$"), true);
                 }
 
+                @Test
+                @TestMetadata("intermediateWithActualAndExpect.kt")
+                public void testIntermediateWithActualAndExpect() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/intermediateWithActualAndExpect.kt");
+                }
+
+                @Test
+                @TestMetadata("kt-55570.kt")
+                public void testKt_55570() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/hmpp/kt-55570.kt");
+                }
+
                 @Test
                 @TestMetadata("sealedInheritorsInComplexModuleStructure.kt")
                 public void testSealedInheritorsInComplexModuleStructure() throws Exception {