code cleanup: 'idea' module

idea/src/org/jetbrains/kotlin/idea/actions/ShowKotlinBytecodeAction.kt

@@ -42,7 +42,7 @@ public class ShowKotlinBytecodeAction(): AnAction() {
             val contentFactory = ContentFactory.SERVICE.getInstance()
             contentManager.addContent(contentFactory.createContent(KotlinBytecodeToolWindow(project, toolWindow), "", false))
         }
-        toolWindow?.activate(null)
+        toolWindow.activate(null)
     }
 
     override fun update(e: AnActionEvent) {

idea/src/org/jetbrains/kotlin/idea/codeInsight/KotlinReferenceTransferableData.kt

@@ -22,7 +22,6 @@ import org.jetbrains.kotlin.resolve.descriptorUtil.getImportableDescriptor
 import org.jetbrains.kotlin.resolve.descriptorUtil.isExtension
 import java.awt.datatransfer.DataFlavor
 import java.io.Serializable
-import kotlin.properties.Delegates
 
 public class KotlinReferenceTransferableData(
         val data: Array<KotlinReferenceData>
@@ -99,7 +98,7 @@ public class KotlinReferenceData(
     }
 
     companion object {
-        public val dataFlavor: DataFlavor? by Delegates.lazy {
+        public val dataFlavor: DataFlavor? by lazy {
             try {
                 val dataClass = javaClass<KotlinReferenceData>()
                 DataFlavor(DataFlavor.javaJVMLocalObjectMimeType + ";class=" + dataClass.getName(),

idea/src/org/jetbrains/kotlin/idea/codeInsight/surroundWith/statement/KotlinStatementSurroundDescriptor.java

@@ -34,11 +34,13 @@ public class KotlinStatementSurroundDescriptor implements SurroundDescriptor {
             new KotlinTryCatchSurrounder()
     };
 
+    @Override
     @NotNull
     public PsiElement[] getElementsToSurround(PsiFile file, int startOffset, int endOffset) {
         return CodeInsightUtils.findStatements(file, startOffset, endOffset);
     }
 
+    @Override
     @NotNull public Surrounder[] getSurrounders() {
         return SURROUNDERS;
     }

idea/src/org/jetbrains/kotlin/idea/configuration/ConfigureKotlinNotificationManager.kt

@@ -35,16 +35,13 @@ object AbsentSdkAnnotationsNotificationManager: KotlinSingleNotificationManager<
     }
 }
 
-trait KotlinSingleNotificationManager<T: Notification> {
+interface KotlinSingleNotificationManager<T: Notification> {
     fun notify(project: Project, notification: T) {
-        val notificationsManager = NotificationsManager.getNotificationsManager()
+        val notificationsManager = NotificationsManager.getNotificationsManager() ?: return
-        if (notificationsManager == null) {
-            return
-        }
 
         var isNotificationExists = false
 
-        val notifications = notificationsManager.getNotificationsOfType(notification.javaClass, project) as Array<Notification>
+        val notifications = notificationsManager.getNotificationsOfType(notification.javaClass, project)
         for (oldNotification in notifications) {
             if (oldNotification == notification) {
                 isNotificationExists = true

idea/src/org/jetbrains/kotlin/idea/debugger/JetPositionManager.kt

@@ -263,7 +263,7 @@ public class JetPositionManager(private val myDebugProcess: DebugProcess) : Mult
             myTypeMappers.put(key, value)
         }
 
-        return value!!.getValue()
+        return value.getValue()
     }
 
     override fun locationsOfLine(type: ReferenceType, position: SourcePosition): List<Location> {

idea/src/org/jetbrains/kotlin/idea/debugger/breakpoints/dialog/AddFieldBreakpointDialog.java

@@ -52,14 +52,17 @@ public abstract class AddFieldBreakpointDialog extends DialogWrapper {
         init();
     }
 
+    @Override
     protected JComponent createCenterPanel() {
         myClassChooser.getTextField().getDocument().addDocumentListener(new DocumentAdapter() {
+            @Override
             public void textChanged(DocumentEvent event) {
                 updateUI();
             }
         });
 
         myClassChooser.addActionListener(new ActionListener() {
+            @Override
             public void actionPerformed(ActionEvent e) {
                 PsiClass currentClass = getSelectedClass();
                 TreeClassChooser chooser = TreeClassChooserFactory.getInstance(myProject).createAllProjectScopeChooser(

idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinEvaluateExpressionCache.kt

@@ -81,7 +81,7 @@ class KotlinEvaluateExpressionCache(val project: Project) {
 
             val thisDescriptor = value.asmType.getClassDescriptor(project)
             val superClassDescriptor = jetType.getConstructor().getDeclarationDescriptor() as? ClassDescriptor
-            return@all thisDescriptor != null && superClassDescriptor != null && runReadAction { DescriptorUtils.isSubclass(thisDescriptor, superClassDescriptor) }!!
+            return@all thisDescriptor != null && superClassDescriptor != null && runReadAction { DescriptorUtils.isSubclass(thisDescriptor, superClassDescriptor) }
         }
     }
 

idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/KotlinRuntimeTypeEvaluator.kt

@@ -84,7 +84,7 @@ public abstract class KotlinRuntimeTypeEvaluator(
             val myValue = value.asValue()
             var psiClass = myValue.asmType.getClassDescriptor(project)
             if (psiClass != null) {
-                return psiClass!!.getDefaultType()
+                return psiClass.getDefaultType()
             }
 
             val type = value.type()
@@ -93,14 +93,14 @@ public abstract class KotlinRuntimeTypeEvaluator(
                 if (superclass != null && CommonClassNames.JAVA_LANG_OBJECT != superclass.name()) {
                     psiClass = AsmType.getType(superclass.signature()).getClassDescriptor(project)
                     if (psiClass != null) {
-                        return psiClass!!.getDefaultType()
+                        return psiClass.getDefaultType()
                     }
                 }
 
                 for (interfaceType in type.interfaces()) {
                     psiClass = AsmType.getType(interfaceType.signature()).getClassDescriptor(project)
                     if (psiClass != null) {
-                        return psiClass!!.getDefaultType()
+                        return psiClass.getDefaultType()
                     }
                 }
             }

idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/compilingEvaluator.kt

@@ -24,7 +24,6 @@ import com.intellij.openapi.projectRoots.JdkVersionUtil
 import com.intellij.openapi.util.SystemInfo
 import com.sun.jdi.ClassLoaderReference
 import org.jetbrains.kotlin.idea.debugger.evaluate.CompilingEvaluatorUtils
-import kotlin.properties.Delegates
 
 public fun loadClasses(evaluationContext: EvaluationContextImpl, classes: Collection<Pair<String, ByteArray>>) {
     val process = evaluationContext.getDebugProcess()
@@ -75,7 +74,7 @@ private val LAMBDA_SUPERCLASSES = listOf(
 )
 
 private class ClassBytes(val name: String) {
-    val bytes: ByteArray by Delegates.lazy {
+    val bytes: ByteArray by lazy {
         val inputStream = this.javaClass.getClassLoader().getResourceAsStream(name.replace('.', '/') + ".class")
                           ?: throw EvaluateException("Couldn't find $name class in current class loader")
 

idea/src/org/jetbrains/kotlin/idea/debugger/evaluate/extractFunctionForDebuggerUtil.kt

@@ -131,7 +131,7 @@ private fun JetFile.getElementInCopy(e: PsiElement): PsiElement? {
         return null
     }
     var elementAt = this.findElementAt(offset)
-    while (elementAt == null || elementAt!!.getTextRange()?.getEndOffset() != e.getTextRange()?.getEndOffset()) {
+    while (elementAt == null || elementAt.getTextRange()?.getEndOffset() != e.getTextRange()?.getEndOffset()) {
         elementAt = elementAt?.getParent()
     }
     return elementAt
@@ -169,7 +169,7 @@ private fun getExpressionToAddDebugExpressionBefore(tmpFile: JetFile, contextEle
             break
         }
 
-        parent = parent?.getParent()
+        parent = parent.getParent()
         parentOfParent = parent?.getParent()
     }
 

idea/src/org/jetbrains/kotlin/idea/editor/KotlinSmartEnterHandler.kt

@@ -67,10 +67,10 @@ public class KotlinSmartEnterHandler: SmartEnterProcessorWithFixers() {
 
         while (atCaret != null) {
             when {
-                atCaret?.isJetStatement() == true -> return atCaret
+                atCaret.isJetStatement() == true -> return atCaret
-                atCaret?.getParent() is JetFunctionLiteral -> return atCaret
+                atCaret.getParent() is JetFunctionLiteral -> return atCaret
                 atCaret is JetDeclaration -> {
-                    val declaration = atCaret!!
+                    val declaration = atCaret
                     when {
                         declaration is JetParameter && !declaration.isInLambdaExpression() -> {/* proceed to function declaration */}
                         declaration.getParent() is JetForExpression -> {/* skip variable declaration in 'for' expression */}
@@ -79,7 +79,7 @@ public class KotlinSmartEnterHandler: SmartEnterProcessorWithFixers() {
                 }
             }
 
-            atCaret = atCaret?.getParent()
+            atCaret = atCaret.getParent()
         }
 
         return null

idea/src/org/jetbrains/kotlin/idea/editor/fixers/KotlinDoWhileFixer.kt

@@ -28,11 +28,10 @@ public class KotlinDoWhileFixer : SmartEnterProcessorWithFixers.Fixer<KotlinSmar
         if (psiElement !is JetDoWhileExpression) return
 
         val doc = editor.getDocument()
-        val stmt = psiElement as JetDoWhileExpression
+        val start = psiElement.range.start
-        val start = stmt.range.start
+        val body = psiElement.getBody()
-        val body = stmt.getBody()
 
-        val whileKeyword = stmt.getWhileKeyword()
+        val whileKeyword = psiElement.getWhileKeyword()
         if (body == null) {
             if (whileKeyword == null) {
                 doc.replaceString(start, start + "do".length(), "do {} while()")
@@ -42,19 +41,19 @@ public class KotlinDoWhileFixer : SmartEnterProcessorWithFixers.Fixer<KotlinSmar
             }
             return
         }
-        else if (whileKeyword != null && body !is JetBlockExpression && body.startLine(doc) > stmt.startLine(doc)) {
+        else if (whileKeyword != null && body !is JetBlockExpression && body.startLine(doc) > psiElement.startLine(doc)) {
             doc.insertString(whileKeyword.range.start, "}")
             doc.insertString(start + "do".length(), "{")
 
             return
         }
 
-        if (stmt.getCondition() == null) {
+        if (psiElement.getCondition() == null) {
-            val lParen = stmt.getLeftParenthesis()
+            val lParen = psiElement.getLeftParenthesis()
-            val rParen = stmt.getRightParenthesis()
+            val rParen = psiElement.getRightParenthesis()
 
             when {
-                whileKeyword == null -> doc.insertString(stmt.range.end, "while()")
+                whileKeyword == null -> doc.insertString(psiElement.range.end, "while()")
                 lParen == null && rParen == null -> {
                     doc.replaceString(whileKeyword.range.start, whileKeyword.range.end, "while()")
                 }

idea/src/org/jetbrains/kotlin/idea/editor/fixers/KotlinMissingIfBranchFixer.kt

@@ -26,11 +26,10 @@ import org.jetbrains.kotlin.psi.JetBlockExpression
 public class KotlinMissingIfBranchFixer : SmartEnterProcessorWithFixers.Fixer<KotlinSmartEnterHandler>() {
     override fun apply(editor: Editor, processor: KotlinSmartEnterHandler, element: PsiElement) {
         if (element !is JetIfExpression) return
-        val ifExpression = element as JetIfExpression
 
         val document = editor.getDocument()
-        val elseBranch = ifExpression.getElse()
+        val elseBranch = element.getElse()
-        val elseKeyword = ifExpression.getElseKeyword()
+        val elseKeyword = element.getElseKeyword()
 
         if (elseKeyword != null) {
             if (elseBranch == null || elseBranch !is JetBlockExpression && elseBranch.startLine(editor.getDocument()) > elseKeyword.startLine(editor.getDocument())) {
@@ -39,15 +38,15 @@ public class KotlinMissingIfBranchFixer : SmartEnterProcessorWithFixers.Fixer<Ko
             }
         }
 
-        val thenBranch = ifExpression.getThen()
+        val thenBranch = element.getThen()
         if (thenBranch is JetBlockExpression) return
 
-        val rParen = ifExpression.getRightParenthesis()
+        val rParen = element.getRightParenthesis()
         if (rParen == null) return
 
         var transformingOneLiner = false
-        if (thenBranch != null && thenBranch.startLine(editor.getDocument()) == ifExpression.startLine(editor.getDocument())) {
+        if (thenBranch != null && thenBranch.startLine(editor.getDocument()) == element.startLine(editor.getDocument())) {
-            if (ifExpression.getCondition() != null) return
+            if (element.getCondition() != null) return
             transformingOneLiner = true
         }
 

idea/src/org/jetbrains/kotlin/idea/editor/fixers/KotlinMissingWhenBodyFixer.kt

@@ -25,15 +25,14 @@ import org.jetbrains.kotlin.psi.JetWhenExpression
 public class KotlinMissingWhenBodyFixer : SmartEnterProcessorWithFixers.Fixer<KotlinSmartEnterHandler>() {
     override fun apply(editor: Editor, processor: KotlinSmartEnterHandler, element: PsiElement) {
         if (element !is JetWhenExpression) return
-        val whenExpression = element as JetWhenExpression
 
         val doc = editor.getDocument()
 
-        val openBrace = whenExpression.getOpenBrace()
+        val openBrace = element.getOpenBrace()
-        val closeBrace = whenExpression.getCloseBrace()
+        val closeBrace = element.getCloseBrace()
 
-        if (openBrace == null && closeBrace == null && whenExpression.getEntries().isEmpty()) {
+        if (openBrace == null && closeBrace == null && element.getEntries().isEmpty()) {
-            val openBraceAfter = whenExpression.insertOpenBraceAfter()
+            val openBraceAfter = element.insertOpenBraceAfter()
             if (openBraceAfter != null) {
                 doc.insertString(openBraceAfter.range.end, "{}")
             }

idea/src/org/jetbrains/kotlin/idea/findUsages/findUsagesOptions.kt

@@ -42,7 +42,7 @@ public class KotlinClassFindUsagesOptions(project: Project) : JavaClassFindUsage
     }
 }
 
-public trait KotlinCallableFindUsagesOptions {
+public interface KotlinCallableFindUsagesOptions {
     public var searchOverrides: Boolean
 }
 
@@ -112,5 +112,5 @@ fun <T : PsiNamedElement> FindUsagesOptions.toSearchTarget(element: T, restrictB
     else
         UsagesSearchLocation.DEFAULT
 
-    return UsagesSearchTarget(element, searchScope ?: element.getUseScope(), location, restrictByTarget)
+    return UsagesSearchTarget(element, searchScope, location, restrictByTarget)
 }

idea/src/org/jetbrains/kotlin/idea/formatter/KotlinSpacingBuilder.kt

@@ -38,7 +38,7 @@ class KotlinSpacingBuilder(val codeStyleSettings: CodeStyleSettings) {
 
     private val builders = ArrayList<Builder>()
 
-    private trait Builder {
+    private interface Builder {
         fun getSpacing(parent: ASTBlock, left: ASTBlock, right: ASTBlock): Spacing?
     }
 

idea/src/org/jetbrains/kotlin/idea/formatter/SyntheticKotlinBlock.kt

@@ -60,17 +60,17 @@ public class SyntheticKotlinBlock(
         loop@
         while (treeNode == null) when (child) {
             is AbstractBlock -> {
-                treeNode = (child as AbstractBlock).getNode()
+                treeNode = child.getNode()
             }
             is SyntheticKotlinBlock -> {
-                child = (child as SyntheticKotlinBlock).getSubBlocks().first()
+                child = child.getSubBlocks().first()
             }
             else -> break@loop
         }
 
         val textRange = getTextRange()
         if (treeNode != null) {
-            val psi = treeNode!!.getPsi()
+            val psi = treeNode.getPsi()
             if (psi != null) {
                 val file = psi.getContainingFile()
                 if (file != null) {

idea/src/org/jetbrains/kotlin/idea/formatter/WrappingStrategy.kt

@@ -19,7 +19,7 @@ package org.jetbrains.kotlin.idea.formatter
 import com.intellij.formatting.Wrap
 import com.intellij.psi.tree.IElementType
 
-public trait WrappingStrategy {
+public interface WrappingStrategy {
     fun getWrap(childElementType: IElementType): Wrap?
 
     object NoWrapping: WrappingStrategy {

idea/src/org/jetbrains/kotlin/idea/highlighter/markers/OverridenPropertyMarker.kt

@@ -123,6 +123,6 @@ public fun isImplemented(declaration: JetNamedDeclaration): Boolean {
 
     if (parent !is JetClass) return false
 
-    return (parent as JetClass).isInterface() && (declaration !is JetDeclarationWithBody || !declaration.hasBody()) && (declaration !is JetWithExpressionInitializer || !declaration.hasInitializer())
+    return parent.isInterface() && (declaration !is JetDeclarationWithBody || !declaration.hasBody()) && (declaration !is JetWithExpressionInitializer || !declaration.hasInitializer())
 }
 

idea/src/org/jetbrains/kotlin/idea/highlighter/markers/SuperDeclarationMarker.kt

@@ -85,7 +85,7 @@ public class SuperDeclarationMarkerNavigationHandler : GutterIconNavigationHandl
             val declarations = DescriptorToSourceUtilsIde.getAllDeclarations(element.getProject(), overriddenMember)
             for (declaration in declarations) {
                 if (declaration is NavigatablePsiElement) {
-                    superDeclarations.add(declaration as NavigatablePsiElement)
+                    superDeclarations.add(declaration)
                 }
             }
         }

idea/src/org/jetbrains/kotlin/idea/liveTemplates/macro/AnonymousTemplateEditingListener.java

@@ -42,10 +42,10 @@ import java.util.Map;
 class AnonymousTemplateEditingListener extends TemplateEditingAdapter {
     private JetReferenceExpression classRef;
     private ClassDescriptor classDescriptor;
-    private Editor editor;
+    private final Editor editor;
     private final PsiFile psiFile;
     
-    private static Map<Editor, AnonymousTemplateEditingListener> ourAddedListeners =
+    private static final Map<Editor, AnonymousTemplateEditingListener> ourAddedListeners =
             new HashMap<Editor, AnonymousTemplateEditingListener>();
 
     public AnonymousTemplateEditingListener(PsiFile psiFile, Editor editor) {

idea/src/org/jetbrains/kotlin/idea/liveTemplates/macro/JetFunctionParametersMacro.java

@@ -30,14 +30,17 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class JetFunctionParametersMacro extends Macro {
+    @Override
     public String getName() {
         return "functionParameters";
     }
 
+    @Override
     public String getPresentableName() {
         return JetBundle.message("macro.fun.parameters");
     }
 
+    @Override
     public Result calculateResult(@NotNull Expression[] params, ExpressionContext context) {
         Project project = context.getProject();
         int templateStartOffset = context.getTemplateStartOffset();

idea/src/org/jetbrains/kotlin/idea/projectView/JetProjectViewProvider.java

@@ -37,7 +37,7 @@ import java.util.Collection;
 import java.util.List;
 
 public class JetProjectViewProvider implements SelectableTreeStructureProvider, DumbAware {
-    private Project myProject;
+    private final Project myProject;
 
     public JetProjectViewProvider(Project project) {
         myProject = project;

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

@@ -64,7 +64,7 @@ public class DeprecatedLambdaSyntaxFix(element: JetFunctionLiteralExpression) :
     }
 }
 
-private trait DeprecatedSyntaxFix {
+private interface DeprecatedSyntaxFix {
     // you must run it under write action
     fun runFix()
 

idea/src/org/jetbrains/kotlin/idea/quickfix/RemoveRightPartOfBinaryExpressionFix.java

@@ -35,6 +35,7 @@ public class RemoveRightPartOfBinaryExpressionFix<T extends JetExpression> exten
         this.message = message;
     }
 
+    @Override
     public String getText() {
         return message;
     }

idea/src/org/jetbrains/kotlin/idea/quickfix/createFromUsage/callableBuilder/CallableBuilder.kt

@@ -49,7 +49,9 @@ import org.jetbrains.kotlin.idea.core.CollectingNameValidator
 import org.jetbrains.kotlin.idea.core.KotlinNameSuggester
 import org.jetbrains.kotlin.idea.core.refactoring.*
 import org.jetbrains.kotlin.idea.quickfix.createFromUsage.createClass.ClassKind
-import org.jetbrains.kotlin.idea.util.*
+import org.jetbrains.kotlin.idea.util.DialogWithEditor
+import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
+import org.jetbrains.kotlin.idea.util.ShortenReferences
 import org.jetbrains.kotlin.idea.util.application.executeWriteCommand
 import org.jetbrains.kotlin.idea.util.application.runWriteAction
 import org.jetbrains.kotlin.lexer.JetTokens
@@ -136,7 +138,7 @@ class CallableBuilder(val config: CallableBuilderConfiguration) {
     val currentFileContext: BindingContext
     val currentFileModule: ModuleDescriptor
 
-    val pseudocode: Pseudocode? by Delegates.lazy { config.originalElement.getContainingPseudocode(currentFileContext) }
+    val pseudocode: Pseudocode? by lazy { config.originalElement.getContainingPseudocode(currentFileContext) }
 
     private val typeCandidates = HashMap<TypeInfo, List<TypeCandidate>>()
 

idea/src/org/jetbrains/kotlin/idea/quickfix/createFromUsage/callableBuilder/CallableInfo.kt

@@ -21,8 +21,6 @@ import com.intellij.util.ArrayUtil
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.idea.core.KotlinNameSuggester
 import org.jetbrains.kotlin.idea.quickfix.createFromUsage.createClass.ClassInfo
-import org.jetbrains.kotlin.types.typeUtil.makeNotNullable
-import org.jetbrains.kotlin.types.typeUtil.supertypes
 import org.jetbrains.kotlin.psi.JetElement
 import org.jetbrains.kotlin.psi.JetExpression
 import org.jetbrains.kotlin.psi.JetTypeReference
@@ -30,8 +28,9 @@ import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.types.ErrorUtils
 import org.jetbrains.kotlin.types.JetType
 import org.jetbrains.kotlin.types.Variance
+import org.jetbrains.kotlin.types.typeUtil.makeNotNullable
+import org.jetbrains.kotlin.types.typeUtil.supertypes
 import java.util.Collections
-import kotlin.properties.Delegates
 
 /**
  * Represents a concrete type or a set of types yet to be inferred from an expression.
@@ -42,7 +41,7 @@ abstract class TypeInfo(val variance: Variance) {
     }
 
     class ByExpression(val expression: JetExpression, variance: Variance): TypeInfo(variance) {
-        override val possibleNamesFromExpression: Array<String> by Delegates.lazy {
+        override val possibleNamesFromExpression: Array<String> by lazy {
             KotlinNameSuggester.suggestNamesByExpressionOnly(expression, { true }).toTypedArray()
         }
 

idea/src/org/jetbrains/kotlin/idea/refactoring/CallableRefactoring.kt

@@ -84,7 +84,7 @@ public abstract class CallableRefactoring<T: CallableDescriptor>(
                                         callableFromEditor.getContainingDeclaration().getName().asString(), superString,
                                         "refactor")
         val title = IdeBundle.message("title.warning")!!
-        val icon = Messages.getQuestionIcon()!!
+        val icon = Messages.getQuestionIcon()
         return Messages.showDialog(message, title, options.toTypedArray(), 0, icon)
     }
 

idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/JetChangeInfo.kt

@@ -48,7 +48,6 @@ import org.jetbrains.kotlin.utils.addToStdlib.singletonOrEmptyList
 import java.util.ArrayList
 import java.util.HashMap
 import java.util.LinkedHashSet
-import kotlin.properties.Delegates
 
 public class JetChangeInfo(
         val methodDescriptor: JetMethodDescriptor,
@@ -72,7 +71,7 @@ public class JetChangeInfo(
     private val newParameters = parameterInfos.toArrayList()
     private val originalPsiMethods: List<PsiMethod> = getMethod().toLightMethods()
 
-    private val oldNameToParameterIndex: Map<String, Int> by Delegates.lazy {
+    private val oldNameToParameterIndex: Map<String, Int> by lazy {
         val map = HashMap<String, Int>()
 
         val parameters = methodDescriptor.baseDescriptor.getValueParameters()
@@ -81,7 +80,7 @@ public class JetChangeInfo(
         map
     }
 
-    public val isParameterSetOrOrderChanged: Boolean by Delegates.lazy {
+    public val isParameterSetOrOrderChanged: Boolean by lazy {
         val signatureParameters = getNonReceiverParameters()
         methodDescriptor.receiver != receiverParameterInfo ||
         signatureParameters.size() != methodDescriptor.getParametersCount() ||

idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/JetChangeSignatureData.kt

@@ -22,7 +22,6 @@ import com.intellij.refactoring.changeSignature.MethodDescriptor
 import com.intellij.refactoring.changeSignature.OverriderUsageInfo
 import com.intellij.usageView.UsageInfo
 import org.jetbrains.kotlin.asJava.KotlinLightMethod
-import org.jetbrains.kotlin.asJava.LightClassUtil
 import org.jetbrains.kotlin.asJava.namedUnwrappedElement
 import org.jetbrains.kotlin.asJava.toLightMethods
 import org.jetbrains.kotlin.descriptors.*
@@ -33,8 +32,6 @@ import org.jetbrains.kotlin.idea.codeInsight.DescriptorToSourceUtilsIde
 import org.jetbrains.kotlin.idea.core.CollectingNameValidator
 import org.jetbrains.kotlin.idea.core.KotlinNameSuggester
 import org.jetbrains.kotlin.idea.refactoring.changeSignature.usages.JetCallableDefinitionUsage
-import org.jetbrains.kotlin.idea.search.declarationsSearch.HierarchySearchRequest
-import org.jetbrains.kotlin.idea.search.declarationsSearch.searchOverriders
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.JetCallableDeclaration
 import org.jetbrains.kotlin.psi.JetClass
@@ -44,7 +41,6 @@ import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import java.util.Collections
 import java.util.HashSet
-import kotlin.properties.Delegates
 
 public class JetChangeSignatureData(
         override val baseDescriptor: CallableDescriptor,
@@ -95,7 +91,7 @@ public class JetChangeSignatureData(
     override val original: JetMethodDescriptor
         get() = this
 
-    override val primaryCallables: Collection<JetCallableDefinitionUsage<PsiElement>> by Delegates.lazy {
+    override val primaryCallables: Collection<JetCallableDefinitionUsage<PsiElement>> by lazy {
         descriptorsForSignatureChange.map {
             val declaration = DescriptorToSourceUtilsIde.getAnyDeclaration(baseDeclaration.getProject(), it)
             assert(declaration != null) { "No declaration found for " + baseDescriptor }
@@ -103,11 +99,11 @@ public class JetChangeSignatureData(
         }
     }
 
-    override val originalPrimaryCallable: JetCallableDefinitionUsage<PsiElement> by Delegates.lazy {
+    override val originalPrimaryCallable: JetCallableDefinitionUsage<PsiElement> by lazy {
         primaryCallables.first { it.getDeclaration() == baseDeclaration }
     }
 
-    override val affectedCallables: Collection<UsageInfo> by Delegates.lazy {
+    override val affectedCallables: Collection<UsageInfo> by lazy {
         primaryCallables + primaryCallables.flatMapTo(HashSet<UsageInfo>()) { primaryFunction ->
             val primaryDeclaration = primaryFunction.getDeclaration() as? JetCallableDeclaration
             val lightMethods = primaryDeclaration?.toLightMethods() ?: Collections.emptyList()

idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/JetMethodDescriptor.kt

@@ -25,7 +25,7 @@ import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.idea.refactoring.changeSignature.usages.JetCallableDefinitionUsage
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
 
-public trait JetMethodDescriptor : MethodDescriptor<JetParameterInfo, Visibility> {
+public interface JetMethodDescriptor : MethodDescriptor<JetParameterInfo, Visibility> {
     enum class Kind(val isConstructor: Boolean) {
         FUNCTION(false),
         PRIMARY_CONSTRUCTOR(true),

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/extractionEngine/ExtractableCodeDescriptor.kt

@@ -31,28 +31,25 @@ import org.jetbrains.kotlin.idea.refactoring.introduce.extractionEngine.Analysis
 import org.jetbrains.kotlin.idea.refactoring.introduce.extractionEngine.OutputValue.ExpressionValue
 import org.jetbrains.kotlin.idea.refactoring.introduce.extractionEngine.OutputValue.Initializer
 import org.jetbrains.kotlin.idea.refactoring.introduce.extractionEngine.OutputValue.Jump
-import org.jetbrains.kotlin.idea.references.JetSimpleNameReference
 import org.jetbrains.kotlin.idea.references.JetSimpleNameReference.ShorteningMode
 import org.jetbrains.kotlin.idea.references.mainReference
 import org.jetbrains.kotlin.idea.util.approximateFlexibleTypes
 import org.jetbrains.kotlin.idea.util.isAnnotatedNotNull
 import org.jetbrains.kotlin.idea.util.isAnnotatedNullable
-import org.jetbrains.kotlin.types.typeUtil.isUnit
 import org.jetbrains.kotlin.idea.util.psi.patternMatching.JetPsiRange
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.getQualifiedElementSelector
 import org.jetbrains.kotlin.psi.psiUtil.getQualifiedExpressionForSelector
-import org.jetbrains.kotlin.psi.psiUtil.getQualifiedExpressionForSelectorOrThis
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.descriptorUtil.resolveTopLevelClass
 import org.jetbrains.kotlin.types.*
+import org.jetbrains.kotlin.types.typeUtil.isUnit
 import java.util.Collections
-import kotlin.properties.Delegates
 
-trait Parameter {
+interface Parameter {
     val argumentText: String
     val originalDescriptor: DeclarationDescriptor
     val name: String
@@ -73,9 +70,9 @@ data class TypeParameter(
         val originalConstraints: List<JetTypeConstraint>
 )
 
-trait Replacement: Function1<JetElement, JetElement>
+interface Replacement: Function1<JetElement, JetElement>
 
-trait ParameterReplacement : Replacement {
+interface ParameterReplacement : Replacement {
     val parameter: Parameter
     fun copy(parameter: Parameter): ParameterReplacement
 }
@@ -124,7 +121,7 @@ class FqNameReplacement(val fqName: FqName): Replacement {
     }
 }
 
-trait OutputValue {
+interface OutputValue {
     val originalExpressions: List<JetExpression>
     val valueType: JetType
 
@@ -207,7 +204,7 @@ abstract class OutputValueBoxer(val outputValues: List<OutputValue>) {
             private val selectors = arrayOf("first", "second", "third")
         }
 
-        override val returnType: JetType by Delegates.lazy {
+        override val returnType: JetType by lazy {
             fun getType(): JetType {
                 val boxingClass = when (outputValues.size()) {
                     1 -> return outputValues.first().valueType
@@ -252,7 +249,7 @@ abstract class OutputValueBoxer(val outputValues: List<OutputValue>) {
     }
 
     class AsList(outputValues: List<OutputValue>): OutputValueBoxer(outputValues) {
-        override val returnType: JetType by Delegates.lazy {
+        override val returnType: JetType by lazy {
             if (outputValues.isEmpty()) DEFAULT_RETURN_TYPE
             else TypeUtils.substituteParameters(
                     KotlinBuiltIns.getInstance().getList(),
@@ -331,7 +328,7 @@ data class ExtractableCodeDescriptor(
         val returnType: JetType
 ) {
     val name: String get() = suggestedNames.firstOrNull() ?: ""
-    val duplicates: List<DuplicateInfo> by Delegates.lazy { findDuplicates() }
+    val duplicates: List<DuplicateInfo> by lazy { findDuplicates() }
 }
 
 enum class ExtractionTarget(val name: String) {

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/extractionEngine/ExtractionData.kt

@@ -16,39 +16,35 @@
 
 package org.jetbrains.kotlin.idea.refactoring.introduce.extractionEngine
 
-import com.intellij.psi.PsiElement
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
-import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.util.TextRange
+import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiNameIdentifierOwner
-import kotlin.properties.Delegates
-import java.util.HashMap
-import org.jetbrains.kotlin.idea.codeInsight.JetFileReferencesResolver
-import org.jetbrains.kotlin.resolve.BindingContext
-import org.jetbrains.kotlin.idea.codeInsight.DescriptorToSourceUtilsIde
-import java.util.Collections
-import org.jetbrains.kotlin.psi.psiUtil.isInsideOf
-import java.util.ArrayList
-import com.intellij.psi.PsiNamedElement
 import com.intellij.psi.util.PsiTreeUtil
-import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
-import org.jetbrains.kotlin.resolve.scopes.receivers.ThisReceiver
-import org.jetbrains.kotlin.descriptors.ClassKind
-import org.jetbrains.kotlin.resolve.calls.model.VariableAsFunctionResolvedCall
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
+import org.jetbrains.kotlin.idea.codeInsight.DescriptorToSourceUtilsIde
+import org.jetbrains.kotlin.idea.codeInsight.JetFileReferencesResolver
 import org.jetbrains.kotlin.idea.core.compareDescriptors
 import org.jetbrains.kotlin.idea.core.refactoring.getContextForContainingDeclarationBody
-import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
-import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 import org.jetbrains.kotlin.idea.util.psi.patternMatching.JetPsiRange
-import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
-import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.getQualifiedExpressionForSelector
+import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
+import org.jetbrains.kotlin.psi.psiUtil.isInsideOf
+import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
+import org.jetbrains.kotlin.resolve.DescriptorUtils
+import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
+import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
+import org.jetbrains.kotlin.resolve.calls.model.VariableAsFunctionResolvedCall
 import org.jetbrains.kotlin.resolve.calls.tasks.isSynthesizedInvoke
 import org.jetbrains.kotlin.resolve.descriptorUtil.isExtension
+import org.jetbrains.kotlin.resolve.scopes.receivers.ThisReceiver
 import org.jetbrains.kotlin.types.JetType
+import java.util.ArrayList
+import java.util.Collections
+import java.util.HashMap
 
 data class ExtractionOptions(
         val inferUnitTypeForUnusedValues: Boolean = true,
@@ -106,7 +102,7 @@ data class ExtractionData(
         }
     }
 
-    val codeFragmentText: String by Delegates.lazy {
+    val codeFragmentText: String by lazy {
         getCodeFragmentTextRange()?.let { originalFile.getText()?.substring(it.getStartOffset(), it.getEndOffset()) } ?: ""
     }
 
@@ -115,12 +111,12 @@ data class ExtractionData(
 
     val commonParent = PsiTreeUtil.findCommonParent(originalElements) as JetElement
 
-    val bindingContext: BindingContext? by Delegates.lazy { commonParent.getContextForContainingDeclarationBody() }
+    val bindingContext: BindingContext? by lazy { commonParent.getContextForContainingDeclarationBody() }
 
-    private val itFakeDeclaration by Delegates.lazy { JetPsiFactory(originalFile).createParameter("it: Any?") }
+    private val itFakeDeclaration by lazy { JetPsiFactory(originalFile).createParameter("it: Any?") }
-    private val synthesizedInvokeDeclaration by Delegates.lazy { JetPsiFactory(originalFile).createFunction("fun invoke() {}") }
+    private val synthesizedInvokeDeclaration by lazy { JetPsiFactory(originalFile).createFunction("fun invoke() {}") }
 
-    val refOffsetToDeclaration by Delegates.lazy {
+    val refOffsetToDeclaration by lazy {
         fun isExtractableIt(descriptor: DeclarationDescriptor, context: BindingContext): Boolean {
             if (!(descriptor is ValueParameterDescriptor && (context[BindingContext.AUTO_CREATED_IT, descriptor] ?: false))) return false
             val function = DescriptorToSourceUtils.descriptorToDeclaration(descriptor.getContainingDeclaration()) as? JetFunctionLiteral

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/extractionEngine/duplicateUtil.kt

@@ -81,7 +81,7 @@ public fun processDuplicates(
                 project,
                 JetRefactoringBundle.message(
                         "0.has.detected.1.code.fragments.in.this.file.that.can.be.replaced.with.a.call.to.extracted.declaration",
-                        ApplicationNamesInfo.getInstance()!!.getProductName(),
+                        ApplicationNamesInfo.getInstance().getProductName(),
                         duplicateReplacers.size()
                 ),
                 "Process Duplicates",

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/extractionEngine/extractableAnalysisUtil.kt

@@ -19,7 +19,6 @@ package org.jetbrains.kotlin.idea.refactoring.introduce.extractionEngine
 import com.intellij.openapi.diagnostic.Logger
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiNamedElement
-import com.intellij.psi.util.PsiTreeUtil
 import com.intellij.refactoring.util.RefactoringUIUtil
 import com.intellij.util.containers.MultiMap
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
@@ -43,14 +42,12 @@ import org.jetbrains.kotlin.idea.caches.resolve.analyzeFully
 import org.jetbrains.kotlin.idea.caches.resolve.findModuleDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
 import org.jetbrains.kotlin.idea.codeInsight.DescriptorToSourceUtilsIde
+import org.jetbrains.kotlin.idea.core.KotlinNameSuggester
+import org.jetbrains.kotlin.idea.core.NewDeclarationNameValidator
 import org.jetbrains.kotlin.idea.core.comparePossiblyOverridingDescriptors
 import org.jetbrains.kotlin.idea.core.getResolutionScope
-import org.jetbrains.kotlin.idea.core.KotlinNameSuggester
 import org.jetbrains.kotlin.idea.core.refactoring.createTempCopy
-import org.jetbrains.kotlin.idea.core.refactoring.getContextForContainingDeclarationBody
 import org.jetbrains.kotlin.idea.imports.importableFqNameSafe
-import org.jetbrains.kotlin.idea.kdoc.getResolutionScope
-import org.jetbrains.kotlin.idea.core.NewDeclarationNameValidator
 import org.jetbrains.kotlin.idea.refactoring.JetRefactoringBundle
 import org.jetbrains.kotlin.idea.refactoring.introduce.extractionEngine.AnalysisResult.ErrorMessage
 import org.jetbrains.kotlin.idea.refactoring.introduce.extractionEngine.AnalysisResult.Status
@@ -63,30 +60,26 @@ import org.jetbrains.kotlin.idea.references.mainReference
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
 import org.jetbrains.kotlin.idea.util.approximateWithResolvableType
 import org.jetbrains.kotlin.idea.util.isResolvableInScope
-import org.jetbrains.kotlin.types.typeUtil.makeNullable
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.*
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
-import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.bindingContextUtil.isUsedAsStatement
-import org.jetbrains.kotlin.resolve.calls.CallTransformer
 import org.jetbrains.kotlin.resolve.calls.callUtil.getCalleeExpressionIfAny
 import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
 import org.jetbrains.kotlin.resolve.calls.tasks.isSynthesizedInvoke
 import org.jetbrains.kotlin.resolve.scopes.JetScope
-import org.jetbrains.kotlin.resolve.scopes.JetScopeUtils
 import org.jetbrains.kotlin.resolve.scopes.receivers.ExpressionReceiver
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
 import org.jetbrains.kotlin.resolve.scopes.receivers.ThisReceiver
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.checker.JetTypeChecker
+import org.jetbrains.kotlin.types.typeUtil.makeNullable
 import org.jetbrains.kotlin.utils.DFS
 import org.jetbrains.kotlin.utils.DFS.CollectingNodeHandler
 import org.jetbrains.kotlin.utils.DFS.Neighbors
 import org.jetbrains.kotlin.utils.DFS.VisitedWithSet
 import java.util.*
-import kotlin.properties.Delegates
 
 private val DEFAULT_RETURN_TYPE = KotlinBuiltIns.getInstance().getUnitType()
 private val DEFAULT_PARAMETER_TYPE = KotlinBuiltIns.getInstance().getNullableAnyType()
@@ -519,12 +512,12 @@ private class MutableParameter(
 
     override var mirrorVarName: String? = null
 
-    private val defaultType: JetType by Delegates.lazy {
+    private val defaultType: JetType by lazy {
         writable = false
         TypeUtils.intersect(JetTypeChecker.DEFAULT, defaultTypes)!!
     }
 
-    private val parameterTypeCandidates: List<JetType> by Delegates.lazy {
+    private val parameterTypeCandidates: List<JetType> by lazy {
         writable = false
 
         val typePredicate = and(typePredicates)

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/introduceParameter/KotlinIntroduceParameterDialog.kt

@@ -166,7 +166,7 @@ public class KotlinIntroduceParameterDialog private constructor(
                     doCancelAction()
                 }
             }
-            parameterTablePanel.init(lambdaExtractionDescriptor!!.receiverParameter, lambdaExtractionDescriptor.parameters)
+            parameterTablePanel.init(lambdaExtractionDescriptor.receiverParameter, lambdaExtractionDescriptor.parameters)
 
             gbConstraints.insets = Insets(4, 4, 4, 8)
             gbConstraints.gridwidth = 1

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/introduceParameter/KotlinIntroduceParameterHandler.kt

@@ -202,7 +202,7 @@ fun selectNewParameterContext(
     )
 }
 
-public trait KotlinIntroduceParameterHelper {
+public interface KotlinIntroduceParameterHelper {
     object Default: KotlinIntroduceParameterHelper
 
     fun configure(descriptor: IntroduceParameterDescriptor): IntroduceParameterDescriptor = descriptor
@@ -390,7 +390,7 @@ private fun findInternalUsagesOfParametersAndReceiver(
     return usages
 }
 
-trait KotlinIntroduceLambdaParameterHelper: KotlinIntroduceParameterHelper {
+interface KotlinIntroduceLambdaParameterHelper: KotlinIntroduceParameterHelper {
     object Default: KotlinIntroduceLambdaParameterHelper
 
     fun configureExtractLambda(descriptor: ExtractableCodeDescriptor): ExtractableCodeDescriptor = descriptor

idea/src/org/jetbrains/kotlin/idea/refactoring/jetRefactoringUtil.kt

@@ -137,7 +137,7 @@ public fun PsiElement.getAllExtractionContainers(strict: Boolean = true): List<J
             is JetBlockExpression, is JetClassBody, is JetFile -> containers.add(element as JetElement)
         }
 
-        element = element!!.getParent()
+        element = element.getParent()
     }
 
     return containers

idea/src/org/jetbrains/kotlin/idea/refactoring/move/moveTopLevelDeclarations/KotlinMoveTarget.kt

@@ -16,17 +16,15 @@
 
 package org.jetbrains.kotlin.idea.refactoring.move.moveTopLevelDeclarations
 
-import com.intellij.refactoring.PackageWrapper
+import com.intellij.openapi.project.Project
-import com.intellij.refactoring.MoveDestination
-import org.jetbrains.kotlin.psi.JetFile
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiFile
 import com.intellij.psi.PsiManager
+import com.intellij.refactoring.PackageWrapper
 import org.jetbrains.kotlin.name.FqName
-import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.psi.JetFile
-import kotlin.properties.Delegates
 
-public trait KotlinMoveTarget {
+public interface KotlinMoveTarget {
     val packageWrapper: PackageWrapper?
     fun getOrCreateTargetPsi(originalPsi: PsiElement): PsiFile?
     fun getTargetPsiIfExists(originalPsi: PsiElement): PsiFile?
@@ -52,7 +50,7 @@ public class DeferredJetFileKotlinMoveTarget(
         project: Project,
         val packageFqName: FqName,
         createFile: () -> JetFile?): KotlinMoveTarget {
-    val createdFile: JetFile? by Delegates.lazy(createFile)
+    val createdFile: JetFile? by lazy(createFile)
 
     override val packageWrapper: PackageWrapper = PackageWrapper(PsiManager.getInstance(project), packageFqName.asString())
 

idea/src/org/jetbrains/kotlin/idea/refactoring/move/moveTopLevelDeclarations/MoveKotlinTopLevelDeclarationsProcessor.kt

@@ -65,7 +65,7 @@ import java.util.ArrayList
 import java.util.HashMap
 import java.util.HashSet
 
-trait Mover: (originalElement: JetNamedDeclaration, targetFile: JetFile) -> JetNamedDeclaration {
+interface Mover: (originalElement: JetNamedDeclaration, targetFile: JetFile) -> JetNamedDeclaration {
     object Default: Mover {
         override fun invoke(originalElement: JetNamedDeclaration, targetFile: JetFile): JetNamedDeclaration {
             val newElement = targetFile.add(originalElement) as JetNamedDeclaration

idea/src/org/jetbrains/kotlin/idea/refactoring/move/moveUtils.kt

@@ -120,7 +120,7 @@ public fun JetElement.getInternalReferencesToUpdateOnPackageNameChange(packageNa
             packageName == packageNameInfo.oldPackageName,
             packageName == packageNameInfo.newPackageName,
             isImported(descriptor) -> {
-                refExpr.mainReference?.let { createMoveUsageInfoIfPossible(it, declaration, false) }
+                createMoveUsageInfoIfPossible(refExpr.mainReference, declaration, false)
             }
 
             else -> null

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

@@ -27,10 +27,9 @@ import org.jetbrains.kotlin.idea.util.application.runReadAction
 import org.jetbrains.kotlin.psi.JetFunction
 import org.jetbrains.kotlin.psi.JetNamedFunction
 import org.jetbrains.kotlin.psi.JetSecondaryConstructor
-import kotlin.properties.Delegates
 
 public class RenameKotlinFunctionProcessor : RenameKotlinPsiProcessor() {
-    private val javaMethodProcessorInstance by Delegates.lazy {
+    private val javaMethodProcessorInstance by lazy {
         // KT-4250
         // RenamePsiElementProcessor.EP_NAME.findExtension(javaClass<RenameJavaMethodProcessor>())!!
 

idea/src/org/jetbrains/kotlin/idea/refactoring/safeDelete/KotlinJavaSafeDeleteDelegate.kt

@@ -38,7 +38,7 @@ public class KotlinJavaSafeDeleteDelegate : JavaSafeDeleteDelegate {
     ) {
         if (reference !is JetReference) return
 
-        val element = reference.getElement() as JetElement
+        val element = reference.getElement()
 
         val callExpression = element.getNonStrictParentOfType<JetCallExpression>()
         if (callExpression == null) return

idea/src/org/jetbrains/kotlin/idea/run/JetRunConfigurationEditor.java

@@ -39,7 +39,7 @@ public class JetRunConfigurationEditor extends SettingsEditor<JetRunConfiguratio
     private CommonJavaParametersPanel myCommonProgramParameters;
     private AlternativeJREPanel alternativeJREPanel;
     private LabeledComponent<JTextField> mainClass;
-    private ConfigurationModuleSelector myModuleSelector;
+    private final ConfigurationModuleSelector myModuleSelector;
     private JComponent anchor;
     private final LabeledComponent<JComboBox> moduleChooser;
 

idea/src/org/jetbrains/kotlin/idea/util/DebuggerUtils.java

@@ -175,7 +175,7 @@ public class DebuggerUtils {
             toProcess.add(containingFile);
         }
 
-        return new kotlin.Pair<BindingContext, List<JetFile>>(context, new ArrayList<JetFile>(toProcess));
+        return new Pair<BindingContext, List<JetFile>>(context, new ArrayList<JetFile>(toProcess));
     }
 
     @NotNull

idea/src/org/jetbrains/kotlin/idea/util/psi/patternMatching/JetPsiRange.kt

@@ -29,7 +29,7 @@ import org.jetbrains.kotlin.idea.util.psi.patternMatching.JetPsiRange.Match
 
 private val SIGNIFICANT_FILTER = { e: PsiElement -> e !is PsiWhiteSpace && e !is PsiComment && e.getTextLength() > 0 }
 
-public trait JetPsiRange {
+public interface JetPsiRange {
     public object Empty : JetPsiRange {
         override val elements: List<PsiElement> get() = Collections.emptyList<PsiElement>()
 

idea/src/org/jetbrains/kotlin/idea/util/psi/patternMatching/JetPsiUnifier.kt

@@ -90,7 +90,7 @@ import org.jetbrains.kotlin.idea.core.refactoring.getContextForContainingDeclara
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
 import org.jetbrains.kotlin.psi.JetOperationReferenceExpression
 
-public trait UnificationResult {
+public interface UnificationResult {
     public enum class Status {
         MATCHED {
             override fun and(other: Status): Status = other
@@ -107,7 +107,7 @@ public trait UnificationResult {
         override val status: Status get() = UNMATCHED
     }
 
-    trait Matched: UnificationResult {
+    interface Matched: UnificationResult {
         val substitution: Map<UnifierParameter, JetExpression>
         override val status: Status get() = MATCHED
     }

idea/src/org/jetbrains/kotlin/plugin/findUsages/handlers/KotlinFindUsagesHandlerDecorator.kt

@@ -20,7 +20,7 @@ import com.intellij.openapi.extensions.ExtensionPointName
 import com.intellij.psi.PsiElement
 import com.intellij.find.findUsages.FindUsagesHandler
 
-public trait KotlinFindUsagesHandlerDecorator {
+public interface KotlinFindUsagesHandlerDecorator {
     companion object {
         public val EP_NAME: ExtensionPointName<KotlinFindUsagesHandlerDecorator> = ExtensionPointName.create("org.jetbrains.kotlin.findUsagesHandlerDecorator")!!
     }

idea/tests/org/jetbrains/kotlin/idea/debugger/AbstractKotlinSteppingTest.kt

@@ -112,7 +112,7 @@ public abstract class AbstractKotlinSteppingTest : KotlinDebuggerTestBase() {
             stepTargets.filterIsInstance<MethodSmartStepTarget>().map {
                 stepTarget ->
                 when (stepTarget) {
-                    is KotlinMethodSmartStepTarget -> KotlinBasicStepMethodFilter(stepTarget as KotlinMethodSmartStepTarget)
+                    is KotlinMethodSmartStepTarget -> KotlinBasicStepMethodFilter(stepTarget)
                     else -> BasicStepMethodFilter(stepTarget.getMethod(), stepTarget.getCallingExpressionLines())
                 }
             }

idea/tests/org/jetbrains/kotlin/idea/refactoring/InplaceRenameTest.kt

@@ -88,7 +88,7 @@ public class InplaceRenameTest : LightPlatformCodeInsightTestCase() {
             assert(range != null)
             object : WriteCommandAction.Simple<Any>(project) {
                 override fun run() {
-                    editor.getDocument().replaceString(range!!.getStartOffset(), range!!.getEndOffset(), newName)
+                    editor.getDocument().replaceString(range!!.getStartOffset(), range.getEndOffset(), newName)
                 }
             }.execute().throwException()
 

idea/tests/org/jetbrains/kotlin/idea/refactoring/introduce/AbstractJetExtractionTest.kt

@@ -228,7 +228,7 @@ public abstract class AbstractJetExtractionTest() : JetLightCodeInsightFixtureTe
             val handler = KotlinIntroducePropertyHandler(helper)
             val editor = fixture.getEditor()
             handler.selectElements(editor, file) { elements, previousSibling ->
-                handler.doInvoke(getProject(), editor, file as JetFile, elements, explicitPreviousSibling ?: previousSibling)
+                handler.doInvoke(getProject(), editor, file, elements, explicitPreviousSibling ?: previousSibling)
             }
         }
     }

idea/tests/org/jetbrains/kotlin/idea/refactoring/rename/AbstractRenameTest.kt

@@ -64,7 +64,7 @@ private enum class RenameType {
     KOTLIN_CLASS,
     KOTLIN_FUNCTION,
     KOTLIN_PROPERTY,
-    KOTLIN_PACKAGE
+    KOTLIN_PACKAGE,
     MARKED_ELEMENT
 }
 

idea/tests/org/jetbrains/kotlin/idea/structureView/AbstractKotlinFileStructureTest.kt

@@ -53,7 +53,7 @@ public abstract class AbstractKotlinFileStructureTest : JetLightCodeInsightFixtu
     }
 
     protected fun FileStructurePopup.setup() {
-        val fileText = FileUtil.loadFile(File(getTestDataPath(), fileName()!!), true)
+        val fileText = FileUtil.loadFile(File(getTestDataPath(), fileName()), true)
 
         val withInherited = InTextDirectivesUtils.isDirectiveDefined(fileText, "WITH_INHERITED")
         setTreeActionState(javaClass<KotlinInheritedMembersNodeProvider>(), withInherited)