FIR: do not inherit external modifier from super declaration

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

@@ -10550,6 +10550,22 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
             }
         }
 
+        @Nested
+        @TestMetadata("compiler/testData/diagnostics/tests/external")
+        @TestDataPath("$PROJECT_ROOT")
+        public class External {
+            @Test
+            public void testAllFilesPresentInExternal() throws Exception {
+                KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/external"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+            }
+
+            @Test
+            @TestMetadata("noExternalModifierInheritance.kt")
+            public void testNoExternalModifierInheritance() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt");
+            }
+        }
+
         @Nested
         @TestMetadata("compiler/testData/diagnostics/tests/funInterface")
         @TestDataPath("$PROJECT_ROOT")

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

@@ -10550,6 +10550,22 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
             }
         }
 
+        @Nested
+        @TestMetadata("compiler/testData/diagnostics/tests/external")
+        @TestDataPath("$PROJECT_ROOT")
+        public class External {
+            @Test
+            public void testAllFilesPresentInExternal() throws Exception {
+                KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/external"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+            }
+
+            @Test
+            @TestMetadata("noExternalModifierInheritance.kt")
+            public void testNoExternalModifierInheritance() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt");
+            }
+        }
+
         @Nested
         @TestMetadata("compiler/testData/diagnostics/tests/funInterface")
         @TestDataPath("$PROJECT_ROOT")

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

@@ -10550,6 +10550,22 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
             }
         }
 
+        @Nested
+        @TestMetadata("compiler/testData/diagnostics/tests/external")
+        @TestDataPath("$PROJECT_ROOT")
+        public class External {
+            @Test
+            public void testAllFilesPresentInExternal() throws Exception {
+                KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/external"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+            }
+
+            @Test
+            @TestMetadata("noExternalModifierInheritance.kt")
+            public void testNoExternalModifierInheritance() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt");
+            }
+        }
+
         @Nested
         @TestMetadata("compiler/testData/diagnostics/tests/funInterface")
         @TestDataPath("$PROJECT_ROOT")

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirStatusResolver.kt

@@ -40,6 +40,7 @@ class FirStatusResolver(
             FirDeclarationStatusImpl.Modifier.CONST,
             FirDeclarationStatusImpl.Modifier.LATEINIT,
             FirDeclarationStatusImpl.Modifier.TAILREC,
+            FirDeclarationStatusImpl.Modifier.EXTERNAL,
         )
 
         private val MODIFIERS_FROM_OVERRIDDEN: List<FirDeclarationStatusImpl.Modifier> =

compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt

@@ -0,0 +1,10 @@
+// FIR_IDENTICAL
+open class A {
+    open external fun foo()
+}
+
+class B : A() {
+    override fun foo() {
+        super.foo()
+    }
+}

compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.txt

@@ -0,0 +1,17 @@
+package
+
+public open class A {
+    public constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open external fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class B : A {
+    public constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Unit
+    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

@@ -10556,6 +10556,22 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
             }
         }
 
+        @Nested
+        @TestMetadata("compiler/testData/diagnostics/tests/external")
+        @TestDataPath("$PROJECT_ROOT")
+        public class External {
+            @Test
+            public void testAllFilesPresentInExternal() throws Exception {
+                KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/tests/external"), Pattern.compile("^(.*)\\.kts?$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+            }
+
+            @Test
+            @TestMetadata("noExternalModifierInheritance.kt")
+            public void testNoExternalModifierInheritance() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/external/noExternalModifierInheritance.kt");
+            }
+        }
+
         @Nested
         @TestMetadata("compiler/testData/diagnostics/tests/funInterface")
         @TestDataPath("$PROJECT_ROOT")