KMP: Put "prohibit expect/actual tailrec/external" under the flag

^KT-61668 Fixed

Review: https://jetbrains.team/p/kt/reviews/12062/timeline

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

@@ -145,6 +145,12 @@ public class FirOldFrontendMPPDiagnosticsWithLightTreeTestGenerated extends Abst
         runTest("compiler/testData/diagnostics/tests/multiplatform/expectExternal.kt");
     }
 
+    @Test
+    @TestMetadata("expectExternal_oldLanguageVersion.kt")
+    public void testExpectExternal_oldLanguageVersion() throws Exception {
+        runTest("compiler/testData/diagnostics/tests/multiplatform/expectExternal_oldLanguageVersion.kt");
+    }
+
     @Test
     @TestMetadata("expectInterfaceApplicability.kt")
     public void testExpectInterfaceApplicability() throws Exception {
@@ -175,6 +181,12 @@ public class FirOldFrontendMPPDiagnosticsWithLightTreeTestGenerated extends Abst
         runTest("compiler/testData/diagnostics/tests/multiplatform/expectTailrec.kt");
     }
 
+    @Test
+    @TestMetadata("expectTailrec_oldLanguageVersion.kt")
+    public void testExpectTailrec_oldLanguageVersion() throws Exception {
+        runTest("compiler/testData/diagnostics/tests/multiplatform/expectTailrec_oldLanguageVersion.kt");
+    }
+
     @Test
     @TestMetadata("headerFunInNonHeaderClass.kt")
     public void testHeaderFunInNonHeaderClass() throws Exception {

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

@@ -145,6 +145,12 @@ public class FirOldFrontendMPPDiagnosticsWithPsiTestGenerated extends AbstractFi
         runTest("compiler/testData/diagnostics/tests/multiplatform/expectExternal.kt");
     }
 
+    @Test
+    @TestMetadata("expectExternal_oldLanguageVersion.kt")
+    public void testExpectExternal_oldLanguageVersion() throws Exception {
+        runTest("compiler/testData/diagnostics/tests/multiplatform/expectExternal_oldLanguageVersion.kt");
+    }
+
     @Test
     @TestMetadata("expectInterfaceApplicability.kt")
     public void testExpectInterfaceApplicability() throws Exception {
@@ -175,6 +181,12 @@ public class FirOldFrontendMPPDiagnosticsWithPsiTestGenerated extends AbstractFi
         runTest("compiler/testData/diagnostics/tests/multiplatform/expectTailrec.kt");
     }
 
+    @Test
+    @TestMetadata("expectTailrec_oldLanguageVersion.kt")
+    public void testExpectTailrec_oldLanguageVersion() throws Exception {
+        runTest("compiler/testData/diagnostics/tests/multiplatform/expectTailrec_oldLanguageVersion.kt");
+    }
+
     @Test
     @TestMetadata("headerFunInNonHeaderClass.kt")
     public void testHeaderFunInNonHeaderClass() throws Exception {

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirExpectActualDeclarationChecker.kt

@@ -76,7 +76,9 @@ object FirExpectActualDeclarationChecker : FirBasicDeclarationChecker() {
         if (declaration is FirProperty) {
             checkExpectPropertyAccessorsModifiers(declaration, context, reporter)
         }
-        if (declaration is FirFunction && declaration.isTailRec) {
+        if (context.languageVersionSettings.supportsFeature(LanguageFeature.MultiplatformRestrictions) &&
+            declaration is FirFunction && declaration.isTailRec
+        ) {
             reporter.reportOn(declaration.source, FirErrors.EXPECTED_TAILREC_FUNCTION, context)
         }
     }
@@ -108,7 +110,9 @@ object FirExpectActualDeclarationChecker : FirBasicDeclarationChecker() {
         context: CheckerContext,
         reporter: DiagnosticReporter,
     ) {
-        if (declaration.isExternal) {
+        if (context.languageVersionSettings.supportsFeature(LanguageFeature.MultiplatformRestrictions) &&
+            declaration.isExternal
+        ) {
             reporter.reportOn(declaration.source, FirErrors.EXPECTED_EXTERNAL_DECLARATION, context)
         }
     }

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

@@ -637,7 +637,7 @@ class DeclarationsChecker(
         }
 
         checkExpectDeclarationHasNoExternalModifier(declaration)
-        if (declaration is KtFunction) {
+        if (declaration is KtFunction && languageVersionSettings.supportsFeature(LanguageFeature.MultiplatformRestrictions)) {
             declaration.modifierList?.getModifier(KtTokens.TAILREC_KEYWORD)?.let {
                 trace.report(EXPECTED_TAILREC_FUNCTION.on(it))
             }
@@ -645,8 +645,10 @@ class DeclarationsChecker(
     }
 
     private fun checkExpectDeclarationHasNoExternalModifier(declaration: KtDeclaration) {
-        declaration.modifierList?.getModifier(KtTokens.EXTERNAL_KEYWORD)?.let {
-            trace.report(EXPECTED_EXTERNAL_DECLARATION.on(it))
+        if (languageVersionSettings.supportsFeature(LanguageFeature.MultiplatformRestrictions)) {
+            declaration.modifierList?.getModifier(KtTokens.EXTERNAL_KEYWORD)?.let {
+                trace.report(EXPECTED_EXTERNAL_DECLARATION.on(it))
+            }
         }
     }
 

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

@@ -0,0 +1,10 @@
+// FIR_IDENTICAL
+// LANGUAGE: -MultiplatformRestrictions
+// MODULE: m1-common
+// FILE: common.kt
+
+expect external fun foo()
+
+// MODULE: m1-jvm()()(m1-common)
+// FILE: jvm.kt
+actual external fun foo()

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

@@ -0,0 +1,9 @@
+// LANGUAGE: -MultiplatformRestrictions
+// MODULE: m1-common
+// FILE: common.kt
+
+expect <!NO_TAIL_CALLS_FOUND!>tailrec<!> fun foo(p: Int): Int
+
+// MODULE: m1-jvm()()(m1-common)
+// FILE: jvm.kt
+actual tailrec fun foo(p: Int): Int = foo(p)

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

@@ -0,0 +1,9 @@
+// LANGUAGE: -MultiplatformRestrictions
+// MODULE: m1-common
+// FILE: common.kt
+
+expect tailrec fun foo(p: Int): Int
+
+// MODULE: m1-jvm()()(m1-common)
+// FILE: jvm.kt
+actual tailrec fun foo(p: Int): Int = foo(p)

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

@@ -23140,6 +23140,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/multiplatform/expectExternal.kt");
             }
 
+            @Test
+            @TestMetadata("expectExternal_oldLanguageVersion.kt")
+            public void testExpectExternal_oldLanguageVersion() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/multiplatform/expectExternal_oldLanguageVersion.kt");
+            }
+
             @Test
             @TestMetadata("expectInterfaceApplicability.kt")
             public void testExpectInterfaceApplicability() throws Exception {
@@ -23170,6 +23176,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/multiplatform/expectTailrec.kt");
             }
 
+            @Test
+            @TestMetadata("expectTailrec_oldLanguageVersion.kt")
+            public void testExpectTailrec_oldLanguageVersion() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/multiplatform/expectTailrec_oldLanguageVersion.kt");
+            }
+
             @Test
             @TestMetadata("headerFunInNonHeaderClass.kt")
             public void testHeaderFunInNonHeaderClass() throws Exception {