Value Classes: Forbid var properties with value class receivers

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

@@ -12957,6 +12957,11 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirOldFronte
             runTest("compiler/testData/diagnostics/tests/inlineClasses/unsignedLiteralsWithoutArtifactOnClasspath.kt");
         }
 
+        @TestMetadata("varPropertyWithInlineClassReceiver.kt")
+        public void testVarPropertyWithInlineClassReceiver() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/inlineClasses/varPropertyWithInlineClassReceiver.kt");
+        }
+
         @TestMetadata("varargsOnParametersOfInlineClassType.kt")
         public void testVarargsOnParametersOfInlineClassType() throws Exception {
             runTest("compiler/testData/diagnostics/tests/inlineClasses/varargsOnParametersOfInlineClassType.kt");

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

@@ -347,7 +347,7 @@ public interface Errors {
     DiagnosticFactory0<PsiElement> NON_PRIVATE_CONSTRUCTOR_IN_ENUM = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> NON_PRIVATE_CONSTRUCTOR_IN_SEALED = DiagnosticFactory0.create(ERROR);
 
-    // Inline classes
+    // Inline and value classes
 
     DiagnosticFactory0<PsiElement> INLINE_CLASS_NOT_TOP_LEVEL = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> INLINE_CLASS_NOT_FINAL = DiagnosticFactory0.create(ERROR);
@@ -355,6 +355,7 @@ public interface Errors {
     DiagnosticFactory0<KtElement> INLINE_CLASS_CONSTRUCTOR_WRONG_PARAMETERS_SIZE = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtParameter> INLINE_CLASS_CONSTRUCTOR_NOT_FINAL_READ_ONLY_PARAMETER = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtProperty> PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
+    DiagnosticFactory0<PsiElement> RESERVED_VAR_PROPERTY_OF_VALUE_CLASS = DiagnosticFactory0.create(WARNING);
     DiagnosticFactory0<PsiElement> DELEGATED_PROPERTY_INSIDE_INLINE_CLASS = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory1<KtTypeReference, KotlinType> INLINE_CLASS_HAS_INAPPLICABLE_PARAMETER_TYPE = DiagnosticFactory1.create(ERROR);
     DiagnosticFactory0<PsiElement> INLINE_CLASS_CANNOT_IMPLEMENT_INTERFACE_BY_DELEGATION = DiagnosticFactory0.create(ERROR);

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

@@ -710,6 +710,7 @@ public class DefaultErrorMessages {
         MAP.put(INLINE_CLASS_CONSTRUCTOR_WRONG_PARAMETERS_SIZE, "Inline class must have exactly one primary constructor parameter");
         MAP.put(INLINE_CLASS_CONSTRUCTOR_NOT_FINAL_READ_ONLY_PARAMETER, "Value class primary constructor must have only final read-only (val) property parameter");
         MAP.put(PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS, "Inline class cannot have properties with backing fields");
+        MAP.put(RESERVED_VAR_PROPERTY_OF_VALUE_CLASS, "'var' properties with value class receivers are reserved for future use");
         MAP.put(DELEGATED_PROPERTY_INSIDE_INLINE_CLASS, "Inline class cannot have delegated properties");
         MAP.put(INLINE_CLASS_HAS_INAPPLICABLE_PARAMETER_TYPE, "Inline class cannot have value parameter of type ''{0}''", RENDER_TYPE);
         MAP.put(INLINE_CLASS_CANNOT_IMPLEMENT_INTERFACE_BY_DELEGATION, "Inline class cannot implement an interface by delegation");

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

@@ -27,8 +27,8 @@ private val DEFAULT_DECLARATION_CHECKERS = listOf(
     KClassWithIncorrectTypeArgumentChecker,
     SuspendLimitationsChecker,
     InlineClassDeclarationChecker,
-    PropertiesWithBackingFieldsInsideInlineClass(),
     InnerClassInsideInlineClass(),
+    PropertiesWithInlineClassAsReceiver(),
     AnnotationClassTargetAndRetentionChecker(),
     ReservedMembersAndConstructsForInlineClass(),
     ResultClassInReturnTypeChecker(),

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

@@ -107,19 +107,27 @@ object InlineClassDeclarationChecker : DeclarationChecker {
     }
 }
 
-class PropertiesWithBackingFieldsInsideInlineClass : DeclarationChecker {
+class PropertiesWithInlineClassAsReceiver : DeclarationChecker {
     override fun check(declaration: KtDeclaration, descriptor: DeclarationDescriptor, context: DeclarationCheckerContext) {
         if (declaration !is KtProperty) return
         if (descriptor !is PropertyDescriptor) return
 
-        if (!descriptor.containingDeclaration.isInlineClass()) return
+        if (descriptor.containingDeclaration.isInlineClass()) {
+            if (context.trace.get(BindingContext.BACKING_FIELD_REQUIRED, descriptor) == true) {
+                context.trace.report(Errors.PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS.on(declaration))
+            }
 
-        if (context.trace.get(BindingContext.BACKING_FIELD_REQUIRED, descriptor) == true) {
+            declaration.delegate?.let {
-            context.trace.report(Errors.PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS.on(declaration))
+                context.trace.report(Errors.DELEGATED_PROPERTY_INSIDE_INLINE_CLASS.on(it))
+            }
         }
 
-        declaration.delegate?.let {
+        if (!descriptor.isVar) return
-            context.trace.report(Errors.DELEGATED_PROPERTY_INSIDE_INLINE_CLASS.on(it))
+
+        if (descriptor.containingDeclaration.isInlineClass() ||
+            descriptor.extensionReceiverParameter?.type?.isInlineClassType() == true
+        ) {
+            context.trace.report(Errors.RESERVED_VAR_PROPERTY_OF_VALUE_CLASS.on(declaration.valOrVarKeyword))
         }
     }
 }

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

@@ -21,8 +21,8 @@ object VarObject {
 
 inline class Z(val data: Int) {
     val testVal <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by Val()<!>
-    var testVar <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by Var()<!>
+    <!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> testVar <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by Var()<!>
 
     val testValBySingleton <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by ValObject<!>
-    var testVarBySingleton <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by VarObject<!>
+    <!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> testVarBySingleton <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by VarObject<!>
 }

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

@@ -15,11 +15,11 @@ inline class Foo(val x: Int) : A, B {
 
     <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>val a1<!> = 0
 
-    var a2: Int
+    <!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> a2: Int
         get() = 1
         set(value) {}
 
-    <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>var a3: Int<!> = 0
+    <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!><!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> a3: Int<!> = 0
         get() = 1
         set(value) {
             field = value
@@ -30,5 +30,5 @@ inline class Foo(val x: Int) : A, B {
 
     <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>override val badSize: Int<!> = 0
 
-    <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>lateinit var lateinitProperty: String<!>
+    <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>lateinit <!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> lateinitProperty: String<!>
 }

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

@@ -0,0 +1,12 @@
+// !LANGUAGE: +InlineClasses
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+inline class IC(val a: Any) {
+    var member: Any
+        get() = a
+        set(value) {}
+}
+
+var IC.extension: Any
+    get() = a
+    set(value) {}

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

@@ -0,0 +1,12 @@
+// !LANGUAGE: +InlineClasses
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+inline class IC(val a: Any) {
+    <!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> member: Any
+        get() = a
+        set(value) {}
+}
+
+<!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> IC.extension: Any
+    get() = a
+    set(value) {}

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

@@ -0,0 +1,12 @@
+package
+
+public var IC.extension: kotlin.Any
+
+public final inline class IC {
+    public constructor IC(/*0*/ a: kotlin.Any)
+    public final val a: kotlin.Any
+    public final var member: kotlin.Any
+    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
+}

compiler/testData/diagnostics/tests/valueClasses/delegatedPropertyInValueClass.kt

@@ -26,8 +26,8 @@ object VarObject {
 @JvmInline
 value class Z(val data: Int) {
     val testVal <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by Val()<!>
-    var testVar <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by Var()<!>
+    <!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> testVar <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by Var()<!>
 
     val testValBySingleton <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by ValObject<!>
-    var testVarBySingleton <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by VarObject<!>
+    <!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> testVarBySingleton <!DELEGATED_PROPERTY_INSIDE_INLINE_CLASS!>by VarObject<!>
 }

compiler/testData/diagnostics/tests/valueClasses/propertiesWithBackingFieldsInsideValueClass.kt

@@ -20,11 +20,11 @@ value class Foo(val x: Int) : A, B {
 
     <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>val a1<!> = 0
 
-    var a2: Int
+    <!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> a2: Int
         get() = 1
         set(value) {}
 
-    <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>var a3: Int<!> = 0
+    <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!><!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> a3: Int<!> = 0
         get() = 1
         set(value) {
             field = value
@@ -35,5 +35,5 @@ value class Foo(val x: Int) : A, B {
 
     <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>override val badSize: Int<!> = 0
 
-    <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>lateinit var lateinitProperty: String<!>
+    <!PROPERTY_WITH_BACKING_FIELD_INSIDE_INLINE_CLASS!>lateinit <!RESERVED_VAR_PROPERTY_OF_VALUE_CLASS!>var<!> lateinitProperty: String<!>
 }

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

@@ -12964,6 +12964,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTestWithFirVali
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/unsignedLiteralsWithoutArtifactOnClasspath.kt");
             }
 
+            @TestMetadata("varPropertyWithInlineClassReceiver.kt")
+            public void testVarPropertyWithInlineClassReceiver() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inlineClasses/varPropertyWithInlineClassReceiver.kt");
+            }
+
             @TestMetadata("varargsOnParametersOfInlineClassType.kt")
             public void testVarargsOnParametersOfInlineClassType() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/varargsOnParametersOfInlineClassType.kt");

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

@@ -12959,6 +12959,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/unsignedLiteralsWithoutArtifactOnClasspath.kt");
             }
 
+            @TestMetadata("varPropertyWithInlineClassReceiver.kt")
+            public void testVarPropertyWithInlineClassReceiver() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inlineClasses/varPropertyWithInlineClassReceiver.kt");
+            }
+
             @TestMetadata("varargsOnParametersOfInlineClassType.kt")
             public void testVarargsOnParametersOfInlineClassType() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/varargsOnParametersOfInlineClassType.kt");