data modifier is now inapplicable to enum classes, annotations, objects and interfaces #KT-8302 Fixed

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

@@ -59,7 +59,7 @@ public object ModifierCheckerCore {
             VARARG_KEYWORD    to EnumSet.of(VALUE_PARAMETER, PROPERTY_PARAMETER),
             COMPANION_KEYWORD to EnumSet.of(OBJECT),
             LATE_INIT_KEYWORD to EnumSet.of(MEMBER_PROPERTY),
-            DATA_KEYWORD      to EnumSet.of(CLASS),
+            DATA_KEYWORD      to EnumSet.of(CLASS_ONLY, INNER_CLASS, LOCAL_CLASS),
             INLINE_KEYWORD    to EnumSet.of(FUNCTION, PROPERTY_GETTER, PROPERTY_SETTER, PROPERTY),
             NOINLINE_KEYWORD  to EnumSet.of(VALUE_PARAMETER),
             TAILREC_KEYWORD   to EnumSet.of(FUNCTION),

compiler/testData/diagnostics/tests/dataClasses/strange.kt

@@ -0,0 +1,10 @@
+<!WRONG_MODIFIER_TARGET!>data<!> enum class First(val x: Int) {
+    A(1),
+    B(2)
+}
+
+<!WRONG_MODIFIER_TARGET!>data<!> object <!DATA_CLASS_WITHOUT_PARAMETERS!>Second<!>
+
+<!WRONG_MODIFIER_TARGET!>data<!> interface <!DATA_CLASS_WITHOUT_PARAMETERS!>Third<!>
+
+<!WRONG_MODIFIER_TARGET!>data<!> annotation class Fourth(val x: Int)

compiler/testData/diagnostics/tests/dataClasses/strange.txt

@@ -0,0 +1,47 @@
+package
+
+@kotlin.data() public final enum class First : kotlin.Enum<First> {
+    enum entry A
+
+    enum entry B
+
+    private constructor First(/*0*/ x: kotlin.Int)
+    public final val x: kotlin.Int
+    protected final override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
+    public final override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: First): kotlin.Int
+    public final /*synthesized*/ fun component1(): kotlin.Int
+    public final /*synthesized*/ fun copy(/*0*/ x: kotlin.Int = ...): First
+    public final override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final override /*1*/ /*fake_override*/ fun name(): kotlin.String
+    public final override /*1*/ /*fake_override*/ fun ordinal(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    // Static members
+    public final /*synthesized*/ fun valueOf(/*0*/ value: kotlin.String): First
+    public final /*synthesized*/ fun values(): kotlin.Array<First>
+}
+
+@kotlin.data() @kotlin.annotation.annotation() public final class Fourth : kotlin.Annotation {
+    public constructor Fourth(/*0*/ x: kotlin.Int)
+    public final val x: kotlin.Int
+    public final /*synthesized*/ fun component1(): kotlin.Int
+    public final /*synthesized*/ fun copy(/*0*/ x: kotlin.Int = ...): Fourth
+    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
+}
+
+@kotlin.data() public object Second {
+    private constructor Second()
+    public final /*synthesized*/ fun copy(): Second
+    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
+}
+
+@kotlin.data() public interface Third {
+    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/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java

@@ -3408,6 +3408,12 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("strange.kt")
+            public void testStrange() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/dataClasses/strange.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("twoValParams.kt")
             public void testTwoValParams() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/dataClasses/twoValParams.kt");

libraries/tools/idl2k/src/main/kotlin/types.kt

@@ -9,13 +9,13 @@ interface Type {
     protected fun String.withSuffix(): String = if (nullable) "$this?" else this
 }
 
-data object UnitType : Type {
+object UnitType : Type {
     override val nullable: Boolean
         get() = false
 
     override fun render() = "Unit"
 }
-data object DynamicType : Type {
+object DynamicType : Type {
     override val nullable: Boolean
         get() = false