[IR] Don't check annotations on expect/actual fake overrides

^KT-58551

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

@@ -256,6 +256,12 @@ public class FirOldFrontendMPPDiagnosticsWithLightTreeTestGenerated extends Abst
             runTest("compiler/testData/diagnostics/tests/multiplatform/annotationMatching/differentOrder.kt");
         }
 
+        @Test
+        @TestMetadata("fakeOverrides.kt")
+        public void testFakeOverrides() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/multiplatform/annotationMatching/fakeOverrides.kt");
+        }
+
         @Test
         @TestMetadata("floatNumbersComparison.kt")
         public void testFloatNumbersComparison() throws Exception {

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

@@ -256,6 +256,12 @@ public class FirOldFrontendMPPDiagnosticsWithPsiTestGenerated extends AbstractFi
             runTest("compiler/testData/diagnostics/tests/multiplatform/annotationMatching/differentOrder.kt");
         }
 
+        @Test
+        @TestMetadata("fakeOverrides.kt")
+        public void testFakeOverrides() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/multiplatform/annotationMatching/fakeOverrides.kt");
+        }
+
         @Test
         @TestMetadata("floatNumbersComparison.kt")
         public void testFloatNumbersComparison() throws Exception {

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

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.ir.symbols.IrSymbol
 import org.jetbrains.kotlin.ir.symbols.IrTypeAliasSymbol
 import org.jetbrains.kotlin.ir.types.IrTypeSystemContext
 import org.jetbrains.kotlin.ir.util.classIdOrFail
+import org.jetbrains.kotlin.ir.util.isFakeOverride
 import org.jetbrains.kotlin.resolve.calls.mpp.AbstractExpectActualAnnotationMatchChecker
 
 internal class IrExpectActualAnnotationMatchingChecker(
@@ -34,6 +35,9 @@ internal class IrExpectActualAnnotationMatchingChecker(
 
     fun check() {
         for ((expectSymbol, actualSymbol) in matchedExpectToActual.entries) {
+            if (expectSymbol.isFakeOverride || actualSymbol.isFakeOverride) {
+                continue
+            }
             val incompatibility =
                 AbstractExpectActualAnnotationMatchChecker.areAnnotationsCompatible(expectSymbol, actualSymbol, context) ?: continue
 
@@ -46,6 +50,9 @@ internal class IrExpectActualAnnotationMatchingChecker(
         }
     }
 
+    private val IrSymbol.isFakeOverride: Boolean
+        get() = (owner as IrDeclaration).isFakeOverride
+
     private fun getTypealiasSymbolIfActualizedViaTypealias(expectSymbol: IrSymbol): IrTypeAliasSymbol? {
         val expectDeclaration = expectSymbol.owner as IrDeclaration
         val topLevelExpectClass = expectDeclaration.parentsWithSelf.filterIsInstance<IrClass>().lastOrNull() ?: return null

compiler/testData/diagnostics/tests/multiplatform/annotationMatching/fakeOverrides.kt

@@ -0,0 +1,32 @@
+// FIR_IDENTICAL
+// MODULE: m1-common
+// FILE: common.kt
+annotation class Ann
+
+interface I {
+    @Ann
+    fun noAnnotationOnActual()
+}
+
+expect class FakeOverrideExpect : I
+
+interface I2 {
+    fun noAnnotationOnActual()
+}
+
+expect class FakeOverrideActual : I2 {
+    @Ann
+    override fun noAnnotationOnActual()
+}
+
+// MODULE: m1-jvm()()(m1-common)
+// FILE: jvm.kt
+actual class FakeOverrideExpect : I {
+    override fun noAnnotationOnActual() {}
+}
+
+abstract class Intermediate : I2 {
+    override fun noAnnotationOnActual() {}
+}
+
+actual class FakeOverrideActual : Intermediate(), I2

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

@@ -22801,6 +22801,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     runTest("compiler/testData/diagnostics/tests/multiplatform/annotationMatching/differentOrder.kt");
                 }
 
+                @Test
+                @TestMetadata("fakeOverrides.kt")
+                public void testFakeOverrides() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/multiplatform/annotationMatching/fakeOverrides.kt");
+                }
+
                 @Test
                 @TestMetadata("floatNumbersComparison.kt")
                 public void testFloatNumbersComparison() throws Exception {