Rename: Drop 'override' keyword when renaming function/property without bases

#KT-4790 Fixed

idea/src/org/jetbrains/kotlin/idea/refactoring/rename/RenameKotlinFunctionProcessor.kt

@@ -20,11 +20,15 @@ import com.intellij.openapi.editor.Editor
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiMethod
 import com.intellij.psi.search.SearchScope
+import com.intellij.refactoring.listeners.RefactoringElementListener
 import com.intellij.refactoring.rename.RenameJavaMethodProcessor
+import com.intellij.usageView.UsageInfo
 import org.jetbrains.kotlin.asJava.KotlinLightMethod
 import org.jetbrains.kotlin.asJava.LightClassUtil
+import org.jetbrains.kotlin.asJava.unwrapped
 import org.jetbrains.kotlin.idea.util.application.runReadAction
 import org.jetbrains.kotlin.psi.JetFunction
+import org.jetbrains.kotlin.psi.JetNamedDeclaration
 import org.jetbrains.kotlin.psi.JetNamedFunction
 import org.jetbrains.kotlin.psi.JetSecondaryConstructor
 
@@ -57,6 +61,12 @@ public class RenameKotlinFunctionProcessor : RenameKotlinPsiProcessor() {
         }
     }
 
+    override fun renameElement(element: PsiElement?, newName: String?, usages: Array<out UsageInfo>?, listener: RefactoringElementListener?) {
+        super.renameElement(element, newName, usages, listener)
+
+        (element?.unwrapped as? JetNamedDeclaration)?.let { dropOverrideKeywordIfNecessary(it) }
+    }
+
     private fun wrapPsiMethod(element: PsiElement?): PsiMethod? = when (element) {
         is KotlinLightMethod -> element
         is JetNamedFunction, is JetSecondaryConstructor -> runReadAction {

idea/src/org/jetbrains/kotlin/idea/refactoring/rename/RenameKotlinPropertyProcessor.kt

@@ -32,17 +32,16 @@ import com.intellij.refactoring.util.RefactoringUtil
 import com.intellij.usageView.UsageInfo
 import org.jetbrains.kotlin.asJava.LightClassUtil
 import org.jetbrains.kotlin.asJava.namedUnwrappedElement
+import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptor
 import org.jetbrains.kotlin.idea.util.application.runReadAction
 import org.jetbrains.kotlin.lexer.JetTokens
 import org.jetbrains.kotlin.load.java.JvmAbi
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.psi.JetCallableDeclaration
-import org.jetbrains.kotlin.psi.JetClassOrObject
-import org.jetbrains.kotlin.psi.JetParameter
-import org.jetbrains.kotlin.psi.JetProperty
+import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 import org.jetbrains.kotlin.resolve.OverrideResolver
@@ -113,7 +112,7 @@ public class RenameKotlinPropertyProcessor : RenamePsiElementProcessor() {
             return
         }
 
-        val name = (element as PsiNamedElement).getName()!!
+        val name = (element as JetNamedDeclaration).getName()!!
         val oldGetterName = JvmAbi.getterName(name)
         val oldSetterName = JvmAbi.setterName(name)
 
@@ -143,6 +142,8 @@ public class RenameKotlinPropertyProcessor : RenamePsiElementProcessor() {
                             refKindUsages[UsageKind.SIMPLE_PROPERTY_USAGE]?.toTypedArray() ?: arrayOf<UsageInfo>(),
                             null)
 
+        dropOverrideKeywordIfNecessary(element)
+
         listener?.elementRenamed(element)
     }
 

idea/src/org/jetbrains/kotlin/idea/refactoring/rename/renameUtil.kt

@@ -21,8 +21,12 @@ import com.intellij.usageView.UsageInfo
 import java.util.ArrayList
 import com.intellij.refactoring.util.MoveRenameUsageInfo
 import com.intellij.refactoring.rename.UnresolvableCollisionUsageInfo
+import org.jetbrains.kotlin.descriptors.CallableDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptor
 import org.jetbrains.kotlin.idea.refactoring.JetRefactoringBundle
 import org.jetbrains.kotlin.idea.references.AbstractJetReference
+import org.jetbrains.kotlin.lexer.JetTokens
+import org.jetbrains.kotlin.psi.JetNamedDeclaration
 
 fun checkConflictsAndReplaceUsageInfos(result: MutableList<UsageInfo>) {
     val usagesToAdd = ArrayList<UsageInfo>()
@@ -50,3 +54,9 @@ class UnresolvableConventionViolationUsageInfo(
 ) : UnresolvableCollisionUsageInfo(element, referencedElement) {
     override fun getDescription(): String = JetRefactoringBundle.message("naming.convention.will.be.violated.after.rename")
 }
+
+fun dropOverrideKeywordIfNecessary(element: JetNamedDeclaration) {
+    if ((element.resolveToDescriptor() as CallableDescriptor).overriddenDescriptors.isEmpty()) {
+        element.removeModifier(JetTokens.OVERRIDE_KEYWORD)
+    }
+}

idea/testData/refactoring/rename/renameEquals/after/equals.kt

@@ -1,5 +1,5 @@
 class A(val n: Int) {
-    override fun foo(other: Any?): Boolean = other is A && other.n == n
+    fun foo(other: Any?): Boolean = other is A && other.n == n
 }
 
 fun test() {