"Redundant visibility": Fix false positive for overridden setter

#KT-26051 Fixed

idea/idea-core/src/org/jetbrains/kotlin/idea/core/psiModificationUtils.kt

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.extensions.DeclarationAttributeAltererExtension
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
 import org.jetbrains.kotlin.idea.references.mainReference
+import org.jetbrains.kotlin.idea.search.usagesSearch.descriptor
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -251,8 +252,20 @@ fun KtModifierListOwner.setVisibility(visibilityModifier: KtModifierKeywordToken
     addModifier(visibilityModifier)
 }
 
-fun KtDeclaration.implicitVisibility(): KtModifierKeywordToken? =
-    when {
+fun KtDeclaration.implicitVisibility(): KtModifierKeywordToken? {
+    if (this is KtPropertyAccessor && this.isSetter) {
+        val property = this.property
+        if (property.hasModifier(KtTokens.OVERRIDE_KEYWORD)) {
+            val visibility = (property.descriptor as? PropertyDescriptor)
+                ?.overriddenDescriptors
+                ?.firstOrNull()
+                ?.setter
+                ?.visibility
+                ?.toKeywordToken()
+            if (visibility != null) return visibility
+        }
+    }
+    return when {
         this is KtConstructor<*> -> {
             val klass = getContainingClassOrObject()
             if (klass is KtClass && (klass.isEnum() || klass.isSealed())) KtTokens.PRIVATE_KEYWORD
@@ -268,6 +281,7 @@ fun KtDeclaration.implicitVisibility(): KtModifierKeywordToken? =
             KtTokens.DEFAULT_VISIBILITY_KEYWORD
         }
     }
+}
 
 fun KtModifierListOwner.canBePrivate() = modifierList?.hasModifier(KtTokens.ABSTRACT_KEYWORD) != true
 

idea/testData/inspectionsLocal/redundantVisibilityModifier/.inspection

@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.inspections.RedundantVisibilityModifierInspection

idea/testData/inspectionsLocal/redundantVisibilityModifier/overridePropertySetter.kt

@@ -0,0 +1,16 @@
+// PROBLEM: none
+
+abstract class Foo {
+    abstract var id: Int
+        protected set
+}
+
+class Bar : Foo() {
+    override var id: Int = 1
+        <caret>public set
+}
+
+fun test() {
+    val bar = Bar()
+    bar.id = 1
+}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -4595,6 +4595,24 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
         }
     }
 
+    @TestMetadata("idea/testData/inspectionsLocal/redundantVisibilityModifier")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class RedundantVisibilityModifier extends AbstractLocalInspectionTest {
+        private void runTest(String testDataFilePath) throws Exception {
+            KotlinTestUtils.runTest(this::doTest, TargetBackend.ANY, testDataFilePath);
+        }
+
+        public void testAllFilesPresentInRedundantVisibilityModifier() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/inspectionsLocal/redundantVisibilityModifier"), Pattern.compile("^([\\w\\-_]+)\\.(kt|kts)$"), TargetBackend.ANY, true);
+        }
+
+        @TestMetadata("overridePropertySetter.kt")
+        public void testOverridePropertySetter() throws Exception {
+            runTest("idea/testData/inspectionsLocal/redundantVisibilityModifier/overridePropertySetter.kt");
+        }
+    }
+
     @TestMetadata("idea/testData/inspectionsLocal/redundantWith")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)