IC: Forbid inner classes inside inline classes

#KT-43067 Fixed

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

@@ -12917,6 +12917,11 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirOldFronte
             runTest("compiler/testData/diagnostics/tests/inlineClasses/inlineClassesInsideAnnotations.kt");
         }
 
+        @TestMetadata("innerClassInsideInlineClass.kt")
+        public void testInnerClassInsideInlineClass() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/inlineClasses/innerClassInsideInlineClass.kt");
+        }
+
         @TestMetadata("lateinitInlineClasses.kt")
         public void testLateinitInlineClasses() throws Exception {
             runTest("compiler/testData/diagnostics/tests/inlineClasses/lateinitInlineClasses.kt");

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -14157,6 +14157,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/inlineClasses/multifileClass.kt");
         }
 
+        @TestMetadata("nestedInlineClass.kt")
+        public void testNestedInlineClass() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt");
+        }
+
         @TestMetadata("noAssertionsOnInlineClassBasedOnNullableType.kt")
         public void testNoAssertionsOnInlineClassBasedOnNullableType() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/noAssertionsOnInlineClassBasedOnNullableType.kt");

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

@@ -362,6 +362,7 @@ public interface Errors {
     DiagnosticFactory0<KtTypeReference> INLINE_CLASS_CANNOT_BE_RECURSIVE = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory1<PsiElement, String> RESERVED_MEMBER_INSIDE_INLINE_CLASS = DiagnosticFactory1.create(ERROR);
     DiagnosticFactory0<PsiElement> SECONDARY_CONSTRUCTOR_WITH_BODY_INSIDE_INLINE_CLASS = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> INNER_CLASS_INSIDE_INLINE_CLASS = DiagnosticFactory0.create(ERROR);
 
     // Result class
 

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

@@ -704,7 +704,7 @@ public class DefaultErrorMessages {
         MAP.put(NON_PRIVATE_CONSTRUCTOR_IN_ENUM, "Constructor must be private in enum class");
         MAP.put(NON_PRIVATE_CONSTRUCTOR_IN_SEALED, "Constructor must be private in sealed class");
 
-        MAP.put(INLINE_CLASS_NOT_TOP_LEVEL, "Inline classes are only allowed on top level");
+        MAP.put(INLINE_CLASS_NOT_TOP_LEVEL, "Inline classes cannot be local or inner");
         MAP.put(INLINE_CLASS_NOT_FINAL, "Inline classes can be only final");
         MAP.put(ABSENCE_OF_PRIMARY_CONSTRUCTOR_FOR_INLINE_CLASS, "Primary constructor is required for inline class");
         MAP.put(INLINE_CLASS_CONSTRUCTOR_WRONG_PARAMETERS_SIZE, "Inline class must have exactly one primary constructor parameter");
@@ -717,6 +717,7 @@ public class DefaultErrorMessages {
         MAP.put(INLINE_CLASS_CANNOT_BE_RECURSIVE, "Inline class cannot be recursive");
         MAP.put(RESERVED_MEMBER_INSIDE_INLINE_CLASS, "Member with the name ''{0}'' is reserved for future releases", STRING);
         MAP.put(SECONDARY_CONSTRUCTOR_WITH_BODY_INSIDE_INLINE_CLASS, "Secondary constructors with bodies are reserved for for future releases");
+        MAP.put(INNER_CLASS_INSIDE_INLINE_CLASS, "Inline class cannot have inner classes");
 
         MAP.put(RESULT_CLASS_IN_RETURN_TYPE, "'kotlin.Result' cannot be used as a return type");
         MAP.put(RESULT_CLASS_WITH_NULLABLE_OPERATOR, "Expression of type 'kotlin.Result' cannot be used as a left operand of ''{0}''", STRING);

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

@@ -28,6 +28,7 @@ private val DEFAULT_DECLARATION_CHECKERS = listOf(
     SuspendLimitationsChecker,
     InlineClassDeclarationChecker,
     PropertiesWithBackingFieldsInsideInlineClass(),
+    InnerClassInsideInlineClass(),
     AnnotationClassTargetAndRetentionChecker(),
     ReservedMembersAndConstructsForInlineClass(),
     ResultClassInReturnTypeChecker(),

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

@@ -29,7 +29,7 @@ object InlineClassDeclarationChecker : DeclarationChecker {
         require(inlineOrValueKeyword != null) { "Declaration of inline class must have 'inline' keyword" }
 
         val trace = context.trace
-        if (!DescriptorUtils.isTopLevelDeclaration(descriptor)) {
+        if (descriptor.isInner || DescriptorUtils.isLocal(descriptor)) {
             trace.report(Errors.INLINE_CLASS_NOT_TOP_LEVEL.on(inlineOrValueKeyword))
             return
         }
@@ -124,6 +124,18 @@ class PropertiesWithBackingFieldsInsideInlineClass : DeclarationChecker {
     }
 }
 
+class InnerClassInsideInlineClass : DeclarationChecker {
+    override fun check(declaration: KtDeclaration, descriptor: DeclarationDescriptor, context: DeclarationCheckerContext) {
+        if (declaration !is KtClass) return
+        if (descriptor !is ClassDescriptor) return
+        if (!descriptor.isInner) return
+
+        if (!descriptor.containingDeclaration.isInlineClass()) return
+
+        context.trace.report(Errors.INNER_CLASS_INSIDE_INLINE_CLASS.on(declaration.modifierList!!.getModifier(KtTokens.INNER_KEYWORD)!!))
+    }
+}
+
 class ReservedMembersAndConstructsForInlineClass : DeclarationChecker {
 
     companion object {

compiler/testData/codegen/box/inlineClasses/kt27705.kt

@@ -2,6 +2,7 @@
 // WITH_RUNTIME
 
 inline class Z(val x: Int) {
+    @Suppress("INNER_CLASS_INSIDE_INLINE_CLASS")
     inner class Inner(val y: Int) {
         val xx = x
     }

compiler/testData/codegen/box/inlineClasses/kt27706.kt

@@ -2,6 +2,7 @@
 // WITH_RUNTIME
 
 inline class Z(val x: Int) {
+    @Suppress("INNER_CLASS_INSIDE_INLINE_CLASS")
     inner class Inner(val z: Z) {
         val xx = x
     }

compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt

@@ -0,0 +1,25 @@
+// !LANGUAGE: +InlineClasses
+
+class C {
+    inline class IC1(val s: String)
+
+    companion object {
+        inline class IC2(val s: String)
+    }
+}
+
+object O {
+    inline class IC3(val s: String)
+}
+
+interface I {
+    inline class IC4(val s: String)
+}
+
+fun box(): String {
+    if (C.IC1("OK").s != "OK") return "FAIL 1"
+    if (C.Companion.IC2("OK").s != "OK") return "FAIL 2"
+    if (O.IC3("OK").s != "OK") return "FAIL 3"
+    if (I.IC4("OK").s != "OK") return "FAIL 4"
+    return "OK"
+}

compiler/testData/codegen/box/reflection/call/inlineClasses/constructorWithInlineClassParameters.kt

@@ -12,6 +12,7 @@ class Outer(val z1: Z) {
 }
 
 inline class InlineOuter(val z1: Z) {
+    @Suppress("INNER_CLASS_INSIDE_INLINE_CLASS")
     inner class Inner(val z2: Z) {
         val test = "$z1 $z2"
     }

compiler/testData/diagnostics/tests/inlineClasses/inlineClassDeclarationCheck.fir.kt

@@ -16,13 +16,20 @@ inline class A9(final val x: Int)
 class B1 {
     companion object {
         inline class C1(val x: Int)
+        inner inline class C11(val x: Int)
     }
 
     inline class C2(val x: Int)
+    inner inline class C21(val x: Int)
 }
 
 object B2 {
     inline class C3(val x: Int)
+    inner inline class C31(val x: Int)
+}
+
+fun foo() {
+    inline class C4(val x: Int)
 }
 
 final inline class D0(val x: Int)

compiler/testData/diagnostics/tests/inlineClasses/inlineClassDeclarationCheck.kt

@@ -15,14 +15,21 @@ inline class A9(final val x: Int)
 
 class B1 {
     companion object {
-        <!INLINE_CLASS_NOT_TOP_LEVEL!>inline<!> class C1(val x: Int)
+        inline class C1(val x: Int)
+        <!WRONG_MODIFIER_CONTAINING_DECLARATION!>inner<!> inline class C11(val x: Int)
     }
 
-    <!INLINE_CLASS_NOT_TOP_LEVEL!>inline<!> class C2(val x: Int)
+    inline class C2(val x: Int)
+    inner <!INLINE_CLASS_NOT_TOP_LEVEL!>inline<!> class C21(val x: Int)
 }
 
 object B2 {
-    <!INLINE_CLASS_NOT_TOP_LEVEL!>inline<!> class C3(val x: Int)
+    inline class C3(val x: Int)
+    <!WRONG_MODIFIER_CONTAINING_DECLARATION!>inner<!> inline class C31(val x: Int)
+}
+
+fun foo() {
+    <!INLINE_CLASS_NOT_TOP_LEVEL, WRONG_MODIFIER_TARGET!>inline<!> class C4(val x: Int)
 }
 
 final inline class D0(val x: Int)

compiler/testData/diagnostics/tests/inlineClasses/inlineClassDeclarationCheck.txt

@@ -1,5 +1,7 @@
 package
 
+public fun foo(): kotlin.Unit
+
 public final inline class A0 {
     public constructor A0(/*0*/ x: kotlin.Int)
     public final val x: kotlin.Int
@@ -92,6 +94,14 @@ public final class B1 {
         public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
     }
 
+    public final inner inline class C21 {
+        public constructor C21(/*0*/ x: kotlin.Int)
+        public final val x: kotlin.Int
+        public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+    }
+
     public companion object Companion {
         private constructor Companion()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
@@ -105,6 +115,14 @@ public final class B1 {
             public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
             public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
         }
+
+        public final inline class C11 {
+            public constructor C11(/*0*/ x: kotlin.Int)
+            public final val x: kotlin.Int
+            public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+            public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+            public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+        }
     }
 }
 
@@ -121,6 +139,14 @@ public object B2 {
         public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
     }
+
+    public final inline class C31 {
+        public constructor C31(/*0*/ x: kotlin.Int)
+        public final val x: kotlin.Int
+        public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+    }
 }
 
 public final inline class D0 {

compiler/testData/diagnostics/tests/inlineClasses/innerClassInsideInlineClass.fir.kt

@@ -0,0 +1,8 @@
+// !LANGUAGE: +InlineClasses
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+inline class Foo(val x: Int) {
+    inner class InnerC
+    inner object InnerO
+    inner interface InnerI
+}

compiler/testData/diagnostics/tests/inlineClasses/innerClassInsideInlineClass.kt

@@ -0,0 +1,8 @@
+// !LANGUAGE: +InlineClasses
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+
+inline class Foo(val x: Int) {
+    <!INNER_CLASS_INSIDE_INLINE_CLASS!>inner<!> class InnerC
+    <!WRONG_MODIFIER_TARGET!>inner<!> object InnerO
+    <!WRONG_MODIFIER_TARGET!>inner<!> interface InnerI
+}

compiler/testData/diagnostics/tests/inlineClasses/innerClassInsideInlineClass.txt

@@ -0,0 +1,29 @@
+package
+
+public final inline class Foo {
+    public constructor Foo(/*0*/ x: kotlin.Int)
+    public final val x: kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+
+    public final inner class InnerC {
+        public constructor InnerC()
+        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 interface InnerI {
+        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 object InnerO {
+        private constructor InnerO()
+        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/valueClasses/valueClassDeclarationCheck.kt

@@ -30,16 +30,16 @@ value class A9(final val x: Int)
 class B1 {
     companion object {
         @JvmInline
-        <!INLINE_CLASS_NOT_TOP_LEVEL!>value<!> class C1(val x: Int)
+        value class C1(val x: Int)
     }
 
     @JvmInline
-    <!INLINE_CLASS_NOT_TOP_LEVEL!>value<!> class C2(val x: Int)
+    value class C2(val x: Int)
 }
 
 object B2 {
     @JvmInline
-    <!INLINE_CLASS_NOT_TOP_LEVEL!>value<!> class C3(val x: Int)
+    value class C3(val x: Int)
 }
 
 @JvmInline

compiler/tests-gen/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -12924,6 +12924,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTestWithFirVali
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/inlineClassesInsideAnnotations.kt");
             }
 
+            @TestMetadata("innerClassInsideInlineClass.kt")
+            public void testInnerClassInsideInlineClass() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inlineClasses/innerClassInsideInlineClass.kt");
+            }
+
             @TestMetadata("lateinitInlineClasses.kt")
             public void testLateinitInlineClasses() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/lateinitInlineClasses.kt");

compiler/tests-gen/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -12919,6 +12919,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/inlineClassesInsideAnnotations.kt");
             }
 
+            @TestMetadata("innerClassInsideInlineClass.kt")
+            public void testInnerClassInsideInlineClass() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inlineClasses/innerClassInsideInlineClass.kt");
+            }
+
             @TestMetadata("lateinitInlineClasses.kt")
             public void testLateinitInlineClasses() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/lateinitInlineClasses.kt");

compiler/tests-gen/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -15557,6 +15557,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/inlineClasses/multifileClass.kt");
         }
 
+        @TestMetadata("nestedInlineClass.kt")
+        public void testNestedInlineClass() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt");
+        }
+
         @TestMetadata("noAssertionsOnInlineClassBasedOnNullableType.kt")
         public void testNoAssertionsOnInlineClassBasedOnNullableType() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/noAssertionsOnInlineClassBasedOnNullableType.kt");

compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -15567,6 +15567,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/inlineClasses/mappingOfBoxedFlexibleInlineClassType.kt");
         }
 
+        @TestMetadata("nestedInlineClass.kt")
+        public void testNestedInlineClass() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt");
+        }
+
         @TestMetadata("noAssertionsOnInlineClassBasedOnNullableType.kt")
         public void testNoAssertionsOnInlineClassBasedOnNullableType() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/noAssertionsOnInlineClassBasedOnNullableType.kt");

compiler/tests-gen/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -14157,6 +14157,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/inlineClasses/multifileClass.kt");
         }
 
+        @TestMetadata("nestedInlineClass.kt")
+        public void testNestedInlineClass() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt");
+        }
+
         @TestMetadata("noAssertionsOnInlineClassBasedOnNullableType.kt")
         public void testNoAssertionsOnInlineClassBasedOnNullableType() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/noAssertionsOnInlineClassBasedOnNullableType.kt");

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java

@@ -12152,6 +12152,11 @@ public class IrJsCodegenBoxES6TestGenerated extends AbstractIrJsCodegenBoxES6Tes
             runTest("compiler/testData/codegen/box/inlineClasses/multifileClass.kt");
         }
 
+        @TestMetadata("nestedInlineClass.kt")
+        public void testNestedInlineClass() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt");
+        }
+
         @TestMetadata("noAssertionsOnInlineClassBasedOnNullableType.kt")
         public void testNoAssertionsOnInlineClassBasedOnNullableType() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/noAssertionsOnInlineClassBasedOnNullableType.kt");

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -12152,6 +12152,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/inlineClasses/multifileClass.kt");
         }
 
+        @TestMetadata("nestedInlineClass.kt")
+        public void testNestedInlineClass() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt");
+        }
+
         @TestMetadata("noAssertionsOnInlineClassBasedOnNullableType.kt")
         public void testNoAssertionsOnInlineClassBasedOnNullableType() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/noAssertionsOnInlineClassBasedOnNullableType.kt");

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -12217,6 +12217,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/inlineClasses/multifileClass.kt");
         }
 
+        @TestMetadata("nestedInlineClass.kt")
+        public void testNestedInlineClass() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt");
+        }
+
         @TestMetadata("noAssertionsOnInlineClassBasedOnNullableType.kt")
         public void testNoAssertionsOnInlineClassBasedOnNullableType() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/noAssertionsOnInlineClassBasedOnNullableType.kt");

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java

@@ -6627,6 +6627,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
             runTest("compiler/testData/codegen/box/inlineClasses/mangledSuperCalls.kt");
         }
 
+        @TestMetadata("nestedInlineClass.kt")
+        public void testNestedInlineClass() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/nestedInlineClass.kt");
+        }
+
         @TestMetadata("noAssertionsOnInlineClassBasedOnNullableType.kt")
         public void testNoAssertionsOnInlineClassBasedOnNullableType() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/noAssertionsOnInlineClassBasedOnNullableType.kt");