Private setters are now deprecated for open properties

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

@@ -340,6 +340,7 @@ public interface Errors {
     DiagnosticFactory0<PsiElement> GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> SETTER_VISIBILITY_DIFFERS_FROM_LATEINIT_VISIBILITY = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> PRIVATE_SETTER_FOR_OPEN_PROPERTY = DiagnosticFactory0.create(WARNING);
     DiagnosticFactory2<KtTypeReference, KotlinType, KotlinType> WRONG_GETTER_RETURN_TYPE = DiagnosticFactory2.create(ERROR);
     DiagnosticFactory0<KtTypeReference> WRONG_SETTER_RETURN_TYPE = DiagnosticFactory0.create(ERROR);
 

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

@@ -211,6 +211,7 @@ public class DefaultErrorMessages {
         MAP.put(GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY, "Getter visibility must be the same as property visibility");
         MAP.put(SETTER_VISIBILITY_DIFFERS_FROM_LATEINIT_VISIBILITY, "Setter visibility must be the same as lateinit property visibility");
         MAP.put(PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY, "Private setters are not allowed for abstract properties");
+        MAP.put(PRIVATE_SETTER_FOR_OPEN_PROPERTY, "Private setters are deprecated for open properties");
         MAP.put(BACKING_FIELD_IN_INTERFACE, "Property in an interface cannot have a backing field");
         MAP.put(MUST_BE_INITIALIZED, "Property must be initialized");
         MAP.put(MUST_BE_INITIALIZED_OR_BE_ABSTRACT, "Property must be initialized or be abstract");

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

@@ -829,10 +829,15 @@ public class DeclarationsChecker {
                 }
             }
             else {
-                if (propertyDescriptor.getModality() == Modality.ABSTRACT
+                if (propertyDescriptor.getModality() != Modality.FINAL
                     && accessorDescriptor.getVisibility() == Visibilities.PRIVATE
                     && propertyDescriptor.getVisibility() != Visibilities.PRIVATE) {
-                    reportVisibilityModifierDiagnostics(tokens.values(), Errors.PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY);
+                    if (propertyDescriptor.getModality() == Modality.ABSTRACT) {
+                        reportVisibilityModifierDiagnostics(tokens.values(), Errors.PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY);
+                    }
+                    else {
+                        reportVisibilityModifierDiagnostics(tokens.values(), Errors.PRIVATE_SETTER_FOR_OPEN_PROPERTY);
+                    }
                 }
                 else if (propertyDescriptor.isLateInit() && accessorDescriptor.getVisibility() != propertyDescriptor.getVisibility()) {
                     reportVisibilityModifierDiagnostics(tokens.values(), Errors.SETTER_VISIBILITY_DIFFERS_FROM_LATEINIT_VISIBILITY);

compiler/testData/diagnostics/tests/AbstractAccessor.kt

@@ -15,4 +15,7 @@ abstract class My {
 
     abstract var u: Int
         protected set
+
+    open var t: Int = 0
+        <!PRIVATE_SETTER_FOR_OPEN_PROPERTY!>private<!> set
 }

compiler/testData/diagnostics/tests/AbstractAccessor.txt

@@ -2,6 +2,7 @@ package
 
 public abstract class My {
     public constructor My()
+    public open var t: kotlin.Int
     public abstract var u: kotlin.Int
     internal abstract val w: kotlin.Int
     public abstract var x: kotlin.Int

compiler/testData/diagnostics/tests/AbstractInTrait.kt

@@ -8,7 +8,7 @@ interface MyTrait {
     <!ABSTRACT_MODIFIER_IN_INTERFACE!>abstract<!> val a3: Int = <!ABSTRACT_PROPERTY_WITH_INITIALIZER!>1<!>
 
     var b: Int                                                                                              <!PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY!>private<!> set
-    var b1: Int = <!PROPERTY_INITIALIZER_IN_INTERFACE!>0<!>;                                                private set
+    var b1: Int = <!PROPERTY_INITIALIZER_IN_INTERFACE!>0<!>;                                                <!PRIVATE_SETTER_FOR_OPEN_PROPERTY!>private<!> set
     <!ABSTRACT_MODIFIER_IN_INTERFACE!>abstract<!> var b2: Int                                               <!PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY!>private<!> set
     <!ABSTRACT_MODIFIER_IN_INTERFACE!>abstract<!> var b3: Int = <!ABSTRACT_PROPERTY_WITH_INITIALIZER!>0<!>; <!PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY!>private<!> set
 

compiler/testData/diagnostics/tests/OverridenSetterVisibility.kt

@@ -13,7 +13,7 @@ abstract class ATest {
 class Test: ATest(), ITest {
     override var prop : Int
         get() = 12
-        <!CANNOT_WEAKEN_ACCESS_PRIVILEGE!>private<!> set(value) {}
+        <!CANNOT_WEAKEN_ACCESS_PRIVILEGE, PRIVATE_SETTER_FOR_OPEN_PROPERTY!>private<!> set(value) {}
 
     override var prop2 : Int
         get() = 14

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

@@ -117,6 +117,7 @@ public class QuickFixRegistrar : QuickFixContributor {
         GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY.registerFactory(removeModifierFactory)
         SETTER_VISIBILITY_DIFFERS_FROM_LATEINIT_VISIBILITY.registerFactory(removeModifierFactory)
         PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY.registerFactory(removeModifierFactory)
+        PRIVATE_SETTER_FOR_OPEN_PROPERTY.registerFactory(removeModifierFactory)
         REDUNDANT_MODIFIER_IN_GETTER.registerFactory(removeRedundantModifierFactory)
         WRONG_MODIFIER_TARGET.registerFactory(removeModifierFactory)
         REDUNDANT_MODIFIER_FOR_TARGET.registerFactory(removeModifierFactory)

idea/testData/checker/Abstract.kt

@@ -71,7 +71,7 @@ interface MyTrait {
     <warning>abstract</warning> val a3: Int = <error>1</error>
 
     var b: Int                                                  <error>private</error> set
-    var b1: Int = <error>0</error>;                             private set
+    var b1: Int = <error>0</error>;                             <warning>private</warning> set
     <warning>abstract</warning> var b2: Int                     <error>private</error> set
     <warning>abstract</warning> var b3: Int = <error>0</error>; <error>private</error> set