Enum entries now can have no initializer if default secondary constructor is available. #KT-8484 Fixed

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

@@ -507,8 +507,7 @@ public class DeclarationsChecker {
         if (DescriptorUtils.isEnumClass(declaration)) {
             ClassDescriptor enumClass = (ClassDescriptor) declaration;
 
-            ConstructorDescriptor constructor = enumClass.getUnsubstitutedPrimaryConstructor();
-            if ((constructor == null || !constructor.getValueParameters().isEmpty()) && !enumEntry.hasInitializer()) {
+            if (!enumEntry.hasInitializer() && !DescriptorUtils.hasDefaultConstructor(enumClass)) {
                 trace.report(ENUM_ENTRY_SHOULD_BE_INITIALIZED.on(enumEntry));
             }
         }

compiler/testData/codegen/box/enum/emptyConstructor.kt

@@ -0,0 +1,8 @@
+package test
+
+enum class My(val s: String) {
+    ENTRY;
+    constructor(): this("OK")
+}
+
+fun box() = My.ENTRY.s

compiler/testData/diagnostics/tests/enum/emptyConstructor.kt

@@ -0,0 +1,4 @@
+enum class E {
+    A; // no constructor call needed
+    constructor()
+}

compiler/testData/diagnostics/tests/enum/emptyConstructor.txt

@@ -0,0 +1,18 @@
+package
+
+internal final enum class E : kotlin.Enum<E> {
+    enum entry A
+
+    private constructor E()
+    protected final override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
+    public final override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: E): kotlin.Int
+    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): E
+    public final /*synthesized*/ fun values(): kotlin.Array<E>
+}

compiler/testData/diagnostics/tests/enum/multipleConstructors.kt

@@ -0,0 +1,8 @@
+enum class E(val x: Int, val y: Int) {
+    A(1, 2),
+    B(1),
+    C; // no constructor call needed even here
+
+    constructor(): this(0, 0)
+    constructor(x: Int): this(x, 0)
+}

compiler/testData/diagnostics/tests/enum/multipleConstructors.txt

@@ -0,0 +1,26 @@
+package
+
+internal final enum class E : kotlin.Enum<E> {
+    enum entry A
+
+    enum entry B
+
+    enum entry C
+
+    private constructor E()
+    private constructor E(/*0*/ x: kotlin.Int)
+    private constructor E(/*0*/ x: kotlin.Int, /*1*/ y: kotlin.Int)
+    internal final val x: kotlin.Int
+    internal final val y: kotlin.Int
+    protected final override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
+    public final override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: E): kotlin.Int
+    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): E
+    public final /*synthesized*/ fun values(): kotlin.Array<E>
+}

compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java

@@ -5199,6 +5199,12 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("emptyConstructor.kt")
+            public void testEmptyConstructor() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/enum/emptyConstructor.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("entryShouldBeOfEnumType.kt")
             public void testEntryShouldBeOfEnumType() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/enum/entryShouldBeOfEnumType.kt");
@@ -5385,6 +5391,12 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("multipleConstructors.kt")
+            public void testMultipleConstructors() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/enum/multipleConstructors.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("openMemberInEnum.kt")
             public void testOpenMemberInEnum() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/enum/openMemberInEnum.kt");

compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxCodegenTestGenerated.java

@@ -3415,6 +3415,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("emptyConstructor.kt")
+        public void testEmptyConstructor() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/emptyConstructor.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("emptyEnumValuesValueOf.kt")
         public void testEmptyEnumValuesValueOf() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/enum/emptyEnumValuesValueOf.kt");

core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.java

@@ -540,6 +540,13 @@ public class DescriptorUtils {
         return !isSingletonOrAnonymousObject(classDescriptor) && !isTrait(classDescriptor);
     }
 
+    public static boolean hasDefaultConstructor(@NotNull ClassDescriptor classDescriptor) {
+        for (ConstructorDescriptor constructor : classDescriptor.getConstructors()) {
+            if (constructor.getValueParameters().isEmpty()) return true;
+        }
+        return false;
+    }
+
     public static Set<FqName> getPackagesFqNames(ModuleDescriptor module) {
         Set<FqName> result = getSubPackagesFqNames(module.getPackage(FqName.ROOT));
         result.add(FqName.ROOT);