REDUNDANT_OPEN_FOR_INTERFACE warning: reported for open members without implementation #KT-12452 Fixed

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

@@ -239,6 +239,8 @@ public interface Errors {
 
     // Interface-specific
 
+    DiagnosticFactory0<KtModifierListOwner> REDUNDANT_OPEN_IN_INTERFACE = DiagnosticFactory0.create(WARNING, OPEN_MODIFIER);
+
     DiagnosticFactory0<KtDeclaration> CONSTRUCTOR_IN_INTERFACE = DiagnosticFactory0.create(ERROR, DECLARATION_SIGNATURE);
     DiagnosticFactory0<KtDeclaration> METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE = DiagnosticFactory0.create(ERROR);
 

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/PositioningStrategies.kt

@@ -195,6 +195,8 @@ object PositioningStrategies {
 
     @JvmField val ABSTRACT_MODIFIER: PositioningStrategy<KtModifierListOwner> = modifierSetPosition(KtTokens.ABSTRACT_KEYWORD)
 
+    @JvmField val OPEN_MODIFIER: PositioningStrategy<KtModifierListOwner> = modifierSetPosition(KtTokens.OPEN_KEYWORD)
+
     @JvmField val OVERRIDE_MODIFIER: PositioningStrategy<KtModifierListOwner> = modifierSetPosition(KtTokens.OVERRIDE_KEYWORD)
 
     @JvmField val PRIVATE_MODIFIER: PositioningStrategy<KtModifierListOwner> = modifierSetPosition(KtTokens.PRIVATE_KEYWORD)

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

@@ -158,6 +158,7 @@ public class DefaultErrorMessages {
         MAP.put(REDUNDANT_ANNOTATION_TARGET, "Redundant annotation target ''{0}''", STRING);
 
         MAP.put(REDUNDANT_MODIFIER, "Modifier ''{0}'' is redundant because ''{1}'' is present", TO_STRING, TO_STRING);
+        MAP.put(REDUNDANT_OPEN_IN_INTERFACE, "Modifier 'open' is redundant for abstract interface members");
         MAP.put(REDUNDANT_MODIFIER_IN_GETTER, "Visibility modifiers are redundant in getter");
         MAP.put(TYPE_PARAMETERS_IN_ENUM, "Enum class cannot have type parameters");
         MAP.put(TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM,

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

@@ -409,7 +409,7 @@ class DeclarationsChecker(
     private fun checkProperty(property: KtProperty, propertyDescriptor: PropertyDescriptor) {
         val containingDeclaration = propertyDescriptor.containingDeclaration
         if (containingDeclaration is ClassDescriptor) {
-            checkPropertyAbstractness(property, propertyDescriptor, containingDeclaration)
+            checkMemberProperty(property, propertyDescriptor, containingDeclaration)
         }
         checkPropertyLateInit(property, propertyDescriptor)
         checkPropertyInitializer(property, propertyDescriptor)
@@ -506,17 +506,24 @@ class DeclarationsChecker(
         }
     }
 
-    private fun checkPropertyAbstractness(
+    private fun checkMemberProperty(
             property: KtProperty,
             propertyDescriptor: PropertyDescriptor,
             classDescriptor: ClassDescriptor) {
         val modifierList = property.modifierList
 
-        if (modifierList != null && modifierList.hasModifier(KtTokens.ABSTRACT_KEYWORD)) {
-            //has abstract modifier
-            if (!classCanHaveAbstractMembers(classDescriptor)) {
-                trace.report(ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS.on(property, property.name ?: "", classDescriptor))
-                return
+        if (modifierList != null) {
+            if (modifierList.hasModifier(KtTokens.ABSTRACT_KEYWORD)) {
+                //has abstract modifier
+                if (!classCanHaveAbstractMembers(classDescriptor)) {
+                    trace.report(ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS.on(property, property.name ?: "", classDescriptor))
+                    return
+                }
+            }
+            else if (classDescriptor.kind == ClassKind.INTERFACE &&
+                modifierList.hasModifier(KtTokens.OPEN_KEYWORD) &&
+                propertyDescriptor.modality == Modality.ABSTRACT) {
+                trace.report(REDUNDANT_OPEN_IN_INTERFACE.on(property))
             }
         }
 
@@ -607,7 +614,7 @@ class DeclarationsChecker(
         val hasExternalModifier = function.hasModifier(KtTokens.EXTERNAL_KEYWORD)
 
         if (containingDescriptor is ClassDescriptor) {
-            val inTrait = containingDescriptor.kind == ClassKind.INTERFACE
+            val inInterface = containingDescriptor.kind == ClassKind.INTERFACE
             if (hasAbstractModifier && !classCanHaveAbstractMembers(containingDescriptor)) {
                 trace.report(ABSTRACT_FUNCTION_IN_NON_ABSTRACT_CLASS.on(function, functionDescriptor.name.asString(), containingDescriptor))
             }
@@ -615,12 +622,15 @@ class DeclarationsChecker(
             if (hasBody && hasAbstractModifier) {
                 trace.report(ABSTRACT_FUNCTION_WITH_BODY.on(function, functionDescriptor))
             }
-            if (!hasBody && inTrait) {
+            if (!hasBody && inInterface) {
                 if (function.hasModifier(KtTokens.PRIVATE_KEYWORD)) {
                     trace.report(PRIVATE_FUNCTION_WITH_NO_BODY.on(function, functionDescriptor))
                 }
+                if (!hasAbstractModifier && function.hasModifier(KtTokens.OPEN_KEYWORD)) {
+                    trace.report(REDUNDANT_OPEN_IN_INTERFACE.on(function))
+                }
             }
-            if (!hasBody && !hasAbstractModifier && !hasExternalModifier && !inTrait) {
+            if (!hasBody && !hasAbstractModifier && !hasExternalModifier && !inInterface) {
                 trace.report(NON_ABSTRACT_FUNCTION_WITH_NO_BODY.on(function, functionDescriptor))
             }
         }

compiler/testData/diagnostics/tests/delegation/Delegation_MultipleDelegates.kt

@@ -1,10 +1,10 @@
 // !DIAGNOSTICS: -CONFLICTING_JVM_DECLARATIONS
 interface One {
-  public open fun foo() : Int
+  public <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun foo() : Int
   private fun boo() = 10
 }
 interface Two {
-  public open fun foo() : Int
+  public <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun foo() : Int
 }
 
 interface OneImpl : One {

compiler/testData/diagnostics/tests/modifiers/openInInterface.kt

@@ -0,0 +1,10 @@
+interface My {
+    <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun foo()
+    open fun bar() {}
+    <!REDUNDANT_MODIFIER!>open<!> abstract fun baz(): Int
+
+    <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> val x: Int
+    open val y: String
+        get() = ""
+    <!REDUNDANT_MODIFIER!>open<!> abstract val z: Double
+}

compiler/testData/diagnostics/tests/modifiers/openInInterface.txt

@@ -0,0 +1,13 @@
+package
+
+public interface My {
+    public abstract val x: kotlin.Int
+    public open val y: kotlin.String
+    public abstract val z: kotlin.Double
+    public open fun bar(): kotlin.Unit
+    public abstract fun baz(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/override/kt880.kt

@@ -1,7 +1,7 @@
 // KT-880 Overload resolution ambiguity
 
 public interface I {
-    open fun test() : Unit
+    <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun test() : Unit
 }
 
 abstract public class A() {

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

@@ -10986,6 +10986,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("openInInterface.kt")
+            public void testOpenInInterface() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/modifiers/openInInterface.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("primaryConstructorMissingKeyword.kt")
             public void testPrimaryConstructorMissingKeyword() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/modifiers/primaryConstructorMissingKeyword.kt");

idea/src/org/jetbrains/kotlin/idea/quickfix/QuickFixRegistrar.kt

@@ -101,6 +101,7 @@ class QuickFixRegistrar : QuickFixContributor {
 
         val removeRedundantModifierFactory = RemoveModifierFix.createRemoveModifierFactory(true)
         REDUNDANT_MODIFIER.registerFactory(removeRedundantModifierFactory)
+        REDUNDANT_OPEN_IN_INTERFACE.registerFactory(removeRedundantModifierFactory)
 
         REDUNDANT_PROJECTION.registerFactory(RemoveModifierFix.createRemoveProjectionFactory(true))
         INCOMPATIBLE_MODIFIERS.registerFactory(RemoveModifierFix.createRemoveModifierFactory(false))