Overriden setter now cannot weaken visibility #KT-3369 Fixed

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

@@ -917,6 +917,13 @@ public class OverrideResolver {
     private void checkVisibility(@NotNull TopDownAnalysisContext c) {
         for (Map.Entry<KtCallableDeclaration, CallableMemberDescriptor> entry : c.getMembers().entrySet()) {
             checkVisibilityForMember(entry.getKey(), entry.getValue());
+            if (entry.getKey() instanceof KtProperty && entry.getValue() instanceof PropertyDescriptor) {
+                KtPropertyAccessor setter = ((KtProperty) entry.getKey()).getSetter();
+                PropertySetterDescriptor setterDescriptor = ((PropertyDescriptor) entry.getValue()).getSetter();
+                if (setter != null && setterDescriptor != null) {
+                    checkVisibilityForMember(setter, setterDescriptor);
+                }
+            }
         }
     }
 

compiler/testData/diagnostics/tests/OverridenSetterVisibility.kt

@@ -0,0 +1,29 @@
+public interface ITest {
+    public var prop : Int
+        get() = 12
+        set(value) {}
+}
+
+abstract class ATest {
+    protected open var prop2 : Int
+        get() = 13
+        set(value) {}
+}
+
+class Test: ATest(), ITest {
+    override var prop : Int
+        get() = 12
+        <!CANNOT_WEAKEN_ACCESS_PRIVILEGE!>private<!> set(value) {}
+
+    override var prop2 : Int
+        get() = 14
+        <!CANNOT_CHANGE_ACCESS_PRIVILEGE!>internal<!> set(value) {}
+}
+
+fun main(args: Array<String>) {
+    val test = Test()
+    <!INVISIBLE_SETTER!>test.prop<!> = 12
+
+    val itest: ITest = test
+    itest.prop = 12 // No error here
+}

compiler/testData/diagnostics/tests/OverridenSetterVisibility.txt

@@ -0,0 +1,27 @@
+package
+
+public fun main(/*0*/ args: kotlin.Array<kotlin.String>): kotlin.Unit
+
+public abstract class ATest {
+    public constructor ATest()
+    protected open var prop2: 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
+}
+
+public interface ITest {
+    public open var prop: 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
+}
+
+public final class Test : ATest, ITest {
+    public constructor Test()
+    public open override /*1*/ var prop: kotlin.Int
+    protected open override /*1*/ var prop2: kotlin.Int
+    public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
+}

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

@@ -433,6 +433,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
             doTest(fileName);
         }
 
+        @TestMetadata("OverridenSetterVisibility.kt")
+        public void testOverridenSetterVisibility() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/OverridenSetterVisibility.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("OverridingVarByVal.kt")
         public void testOverridingVarByVal() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/OverridingVarByVal.kt");