KT-322 Prohibit inheriting classes from enums

#KT-322 Fixed

compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/Errors.java

@@ -68,6 +68,8 @@ public interface Errors {
             .create(WARNING, ABSTRACT_MODIFIER);
     SimpleDiagnosticFactory<JetModifierListOwner> OPEN_MODIFIER_IN_TRAIT = SimpleDiagnosticFactory
             .create(WARNING, positionModifier(JetTokens.OPEN_KEYWORD));
+    SimpleDiagnosticFactory<JetModifierListOwner> OPEN_MODIFIER_IN_ENUM = SimpleDiagnosticFactory
+            .create(ERROR, positionModifier(JetTokens.OPEN_KEYWORD));
     SimpleDiagnosticFactory<PsiElement>
             REDUNDANT_MODIFIER_IN_GETTER = SimpleDiagnosticFactory.create(WARNING);
     SimpleDiagnosticFactory<PsiElement> TRAIT_CAN_NOT_BE_FINAL = SimpleDiagnosticFactory.create(ERROR);

compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/rendering/DefaultErrorMessages.java

@@ -81,6 +81,7 @@ public class DefaultErrorMessages {
         MAP.put(REDUNDANT_MODIFIER, "Modifier ''{0}'' is redundant because ''{1}'' is present", TO_STRING, TO_STRING);
         MAP.put(ABSTRACT_MODIFIER_IN_TRAIT, "Modifier ''abstract'' is redundant in trait");
         MAP.put(OPEN_MODIFIER_IN_TRAIT, "Modifier ''open'' is redundant in trait");
+        MAP.put(OPEN_MODIFIER_IN_ENUM, "Modifier ''open'' is not applicable for enum class");
         MAP.put(REDUNDANT_MODIFIER_IN_GETTER, "Visibility modifiers are redundant in getter");
         MAP.put(TRAIT_CAN_NOT_BE_FINAL, "Trait cannot be final");
         MAP.put(TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM,

compiler/frontend/src/org/jetbrains/jet/lang/resolve/DeclarationsChecker.java

@@ -19,7 +19,6 @@ package org.jetbrains.jet.lang.resolve;
 import com.google.common.collect.Sets;
 import com.intellij.lang.ASTNode;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.descriptors.*;
 import org.jetbrains.jet.lang.diagnostics.Errors;
 import org.jetbrains.jet.lang.psi.*;
@@ -94,12 +93,18 @@ public class DeclarationsChecker {
 
     private void checkClass(JetClass aClass, MutableClassDescriptor classDescriptor) {
         checkOpenMembers(classDescriptor);
-        checkTraitModifiers(aClass);
-        checkEnum(aClass, classDescriptor);
+        if (aClass.isTrait()) {
+            checkTraitModifiers(aClass);
+        }
+        else if (aClass.hasModifier(JetTokens.ENUM_KEYWORD)) {
+            checkEnumModifiers(aClass);
+        }
+        else if (classDescriptor.getKind() == ClassKind.ENUM_ENTRY) {
+            checkEnumEntry(aClass, classDescriptor);
+        }
     }
 
     private void checkTraitModifiers(JetClass aClass) {
-        if (!aClass.isTrait()) return;
         JetModifierList modifierList = aClass.getModifierList();
         if (modifierList == null) return;
         if (modifierList.hasModifier(JetTokens.FINAL_KEYWORD)) {
@@ -295,11 +300,13 @@ public class DeclarationsChecker {
         }
     }
 
+    private void checkEnumModifiers(JetClass aClass) {
+        if (aClass.hasModifier(JetTokens.OPEN_KEYWORD)) {
+            trace.report(OPEN_MODIFIER_IN_ENUM.on(aClass));
+        }
+    }
 
-
-    private void checkEnum(JetClass aClass, ClassDescriptor classDescriptor) {
-        if (classDescriptor.getKind() != ClassKind.ENUM_ENTRY) return;
-
+    private void checkEnumEntry(JetClass aClass, ClassDescriptor classDescriptor) {
         DeclarationDescriptor declaration = classDescriptor.getContainingDeclaration().getContainingDeclaration();
         assert declaration instanceof ClassDescriptor;
         ClassDescriptorFromSource enumClass = (ClassDescriptorFromSource) declaration;

compiler/testData/diagnostics/tests/DelegationNotTotrait.kt

@@ -8,7 +8,7 @@ trait T {}
 
 class Br(t : T) : T by t {}
 
-open enum class EN() {
+<!OPEN_MODIFIER_IN_ENUM!>open<!> enum class EN() {
   A
 }
 

compiler/testData/diagnostics/tests/declarationChecks/kt1193.kt

@@ -2,7 +2,7 @@
 
 package kt1193
 
-open enum class MyEnum(val i: Int) {
+enum class MyEnum(val i: Int) {
     A : MyEnum(12)
     <!ENUM_ENTRY_SHOULD_BE_INITIALIZED!>B<!>  //no error
 }

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

@@ -0,0 +1,13 @@
+// FILE: MyJavaEnum.java
+public enum MyJavaEnum {}
+
+// FILE: test.kt
+<!OPEN_MODIFIER_IN_ENUM!>open<!> enum class MyEnum() {
+    A: MyEnum()
+}
+
+enum class MyEnum2() {}
+
+class MyClass(): <!INVISIBLE_MEMBER, FINAL_SUPERTYPE!>MyEnum2<!>() {}
+
+class MyClass2(): <!FINAL_SUPERTYPE!>MyJavaEnum<!>() {}

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

@@ -1244,6 +1244,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 doTest("compiler/testData/diagnostics/tests/enum/importEnumFromJava.kt");
             }
             
+            @TestMetadata("inheritanceFromEnum.kt")
+            public void testInheritanceFromEnum() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/enum/inheritanceFromEnum.kt");
+            }
+            
             @TestMetadata("javaEnumValueOfMethod.kt")
             public void testJavaEnumValueOfMethod() throws Exception {
                 doTest("compiler/testData/diagnostics/tests/enum/javaEnumValueOfMethod.kt");