Setter visibility must be worse or the same as property visibility

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

@@ -358,6 +358,7 @@ public interface Errors {
     DiagnosticFactory0<PsiElement> REDUNDANT_MODIFIER_IN_GETTER = DiagnosticFactory0.create(WARNING);
     DiagnosticFactory0<PsiElement> GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> SETTER_VISIBILITY_DIFFERS_FROM_LATEINIT_VISIBILITY = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> PRIVATE_SETTER_FOR_OPEN_PROPERTY = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory2<KtTypeReference, KotlinType, KotlinType> WRONG_GETTER_RETURN_TYPE = DiagnosticFactory2.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(SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY, "Setter visibility must be the same or less permissive than 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");

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

@@ -718,6 +718,12 @@ class DeclarationsChecker(
             else if (propertyDescriptor.isLateInit && accessorDescriptor.visibility != propertyDescriptor.visibility) {
                 reportVisibilityModifierDiagnostics(tokens.values, Errors.SETTER_VISIBILITY_DIFFERS_FROM_LATEINIT_VISIBILITY)
             }
+            else {
+                val compare = Visibilities.compare(accessorDescriptor.visibility, propertyDescriptor.visibility)
+                if (compare == null || compare > 0) {
+                    reportVisibilityModifierDiagnostics(tokens.values, Errors.SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY)
+                }
+            }
         }
     }
 

compiler/testData/diagnostics/tests/OverridenSetterVisibility.kt

@@ -17,7 +17,7 @@ class Test: ATest(), ITest {
 
     override var prop2 : Int
         get() = 14
-        <!CANNOT_CHANGE_ACCESS_PRIVILEGE!>internal<!> set(value) {}
+        <!CANNOT_CHANGE_ACCESS_PRIVILEGE, SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY!>internal<!> set(value) {}
 }
 
 fun main(args: Array<String>) {

compiler/testData/diagnostics/tests/SetterVisibility.kt

@@ -0,0 +1,25 @@
+class My {
+    var x: Int = 0
+        // Ok
+        private set
+    
+    private var y: Int = 1
+        // Error: better
+        <!SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY!>public<!> set
+
+    protected var z: Int = 2
+        // Ok
+        private set
+
+    protected var w: Int = 3
+        // Error: incompatible
+        <!SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY!>internal<!> set
+
+    internal var v: Int = 4
+        // Error: incompatible
+        <!SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY!>protected<!> set
+
+    internal var t: Int = 5
+        // Error: better
+        <!SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY!>public<!> set
+}

compiler/testData/diagnostics/tests/SetterVisibility.txt

@@ -0,0 +1,14 @@
+package
+
+public final class My {
+    public constructor My()
+    internal final var t: kotlin.Int
+    internal final var v: kotlin.Int
+    protected final var w: kotlin.Int
+    public final var x: kotlin.Int
+    private final var y: kotlin.Int
+    protected final var z: kotlin.Int
+    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/testData/loadJava/compiledKotlin/prop/defaultAccessors/ClassVarWithSet.kt

@@ -16,12 +16,6 @@ class ClassVal() {
     protected var property5: String = ""
       private set
 
-    protected var property6: String = ""
-      internal set
-
-    protected var property7: java.util.Date = java.util.Date()
-      public set
-
     public var property8: Int = 1
       set
 

compiler/testData/loadJava/compiledKotlin/prop/defaultAccessors/ClassVarWithSet.txt

@@ -23,12 +23,6 @@ public final class ClassVal {
     protected final var property5: kotlin.String
         protected final fun <get-property5>(): kotlin.String
         private final fun <set-property5>(/*0*/ <set-?>: kotlin.String): kotlin.Unit
-    protected final var property6: kotlin.String
-        protected final fun <get-property6>(): kotlin.String
-        internal final fun <set-property6>(/*0*/ <set-?>: kotlin.String): kotlin.Unit
-    protected final var property7: java.util.Date
-        protected final fun <get-property7>(): java.util.Date
-        public final fun <set-property7>(/*0*/ <set-?>: java.util.Date): kotlin.Unit
     public final var property8: kotlin.Int
         public final fun <get-property8>(): kotlin.Int
         public final fun <set-property8>(/*0*/ <set-?>: kotlin.Int): kotlin.Unit

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

@@ -595,6 +595,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
             doTest(fileName);
         }
 
+        @TestMetadata("SetterVisibility.kt")
+        public void testSetterVisibility() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/SetterVisibility.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("ShiftFunctionTypes.kt")
         public void testShiftFunctionTypes() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/ShiftFunctionTypes.kt");

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

@@ -115,6 +115,7 @@ public class QuickFixRegistrar : QuickFixContributor {
         val removeModifierFactory = RemoveModifierFix.createRemoveModifierFactory()
         GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY.registerFactory(removeModifierFactory)
         SETTER_VISIBILITY_DIFFERS_FROM_LATEINIT_VISIBILITY.registerFactory(removeModifierFactory)
+        SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY.registerFactory(removeModifierFactory)
         PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY.registerFactory(removeModifierFactory)
         PRIVATE_SETTER_FOR_OPEN_PROPERTY.registerFactory(removeModifierFactory)
         REDUNDANT_MODIFIER_IN_GETTER.registerFactory(removeRedundantModifierFactory)