diff --git a/compiler/frontend/src/org/jetbrains/kotlin/cfg/UnreachableCode.kt b/compiler/frontend/src/org/jetbrains/kotlin/cfg/UnreachableCode.kt
index 5504c179b56..8d7ea3c4106 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/cfg/UnreachableCode.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/cfg/UnreachableCode.kt
@@ -16,17 +16,16 @@
 
 package org.jetbrains.kotlin.cfg
 
-import org.jetbrains.kotlin.psi.JetElement
 import com.intellij.openapi.util.TextRange
-import java.util.HashSet
-import org.jetbrains.kotlin.psi.JetPsiUtil
+import com.intellij.psi.PsiComment
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiElementVisitor
 import com.intellij.psi.PsiWhiteSpace
-import java.util.ArrayList
-import org.jetbrains.kotlin.lexer.JetTokens
 import com.intellij.psi.util.PsiTreeUtil
-import com.intellij.psi.PsiComment
+import org.jetbrains.kotlin.lexer.JetTokens
+import org.jetbrains.kotlin.psi.JetElement
+import org.jetbrains.kotlin.psi.JetPsiUtil
+import java.util.*
 
 interface UnreachableCode {
     val elements: Set<JetElement>
@@ -99,7 +98,7 @@ class UnreachableCodeImpl(
 
     private fun List<PsiElement>.mergeAdjacentTextRanges(): List<TextRange> {
         val result = ArrayList<TextRange>()
-        val lastRange = fold(null: TextRange?) {
+        val lastRange = fold(null as TextRange?) {
             currentTextRange, element ->
 
             val elementRange = element.getTextRange()!!
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/psi/JetOperationReferenceExpression.kt b/compiler/frontend/src/org/jetbrains/kotlin/psi/JetOperationReferenceExpression.kt
index bf82fe1eaca..edcdbad4988 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/psi/JetOperationReferenceExpression.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/psi/JetOperationReferenceExpression.kt
@@ -17,16 +17,16 @@
 package org.jetbrains.kotlin.psi
 
 import com.intellij.lang.ASTNode
-import org.jetbrains.kotlin.parsing.JetExpressionParsing
 import com.intellij.psi.PsiElement
 import com.intellij.psi.impl.source.tree.TreeElement
 import org.jetbrains.kotlin.lexer.JetSingleValueToken
 import org.jetbrains.kotlin.lexer.JetToken
 import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.parsing.JetExpressionParsing
 import org.jetbrains.kotlin.types.expressions.OperatorConventions
 
 public class JetOperationReferenceExpression(node: ASTNode) : JetSimpleNameExpressionImpl(node) {
-    override fun getReferencedNameElement() = (findChildByType(JetExpressionParsing.ALL_OPERATIONS): PsiElement?) ?: this
+    override fun getReferencedNameElement() = findChildByType<PsiElement?>(JetExpressionParsing.ALL_OPERATIONS) ?: this
 
     fun getNameForConventionalOperation(unaryOperations: Boolean = true, binaryOperations: Boolean = true): Name? {
         val operator = (firstChild as? TreeElement)?.elementType as? JetToken ?: return null
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/TaskPrioritizer.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/TaskPrioritizer.kt
index 7ebf8d08dfa..dace6fb013c 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/TaskPrioritizer.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/TaskPrioritizer.kt
@@ -21,7 +21,9 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.incremental.KotlinLookupLocation
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.progress.ProgressIndicatorAndCompilationCanceledStatus
-import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.Call
+import org.jetbrains.kotlin.psi.JetFile
+import org.jetbrains.kotlin.psi.doNotAnalyze
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.calls.callResolverUtil.isConventionCall
 import org.jetbrains.kotlin.resolve.calls.callResolverUtil.isOrOverridesSynthesized
@@ -484,7 +486,7 @@ public class TaskPrioritizer(
 
         private fun isSynthesized(candidate: ResolutionCandidate<D>): Boolean {
             val descriptor = candidate.getDescriptor()
-            return descriptor is CallableMemberDescriptor && isOrOverridesSynthesized(descriptor : CallableMemberDescriptor)
+            return descriptor is CallableMemberDescriptor && isOrOverridesSynthesized(descriptor)
         }
 
         fun hasImplicitDynamicReceiver(candidate: ResolutionCandidate<D>): Boolean {
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/dynamicCalls.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/dynamicCalls.kt
index e883fceae85..2a4fa6a111c 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/dynamicCalls.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tasks/dynamicCalls.kt
@@ -104,7 +104,7 @@ class DynamicCallableDescriptors(private val builtIns: KotlinBuiltIns) {
                 dynamicType,
                 createTypeParameters(propertyDescriptor, call),
                 createDynamicDispatchReceiverParameter(propertyDescriptor),
-                null: JetType?
+                null as JetType?
         )
 
         val getter = DescriptorFactory.createDefaultGetter(propertyDescriptor, Annotations.EMPTY)
diff --git a/js/js.translator/src/org/jetbrains/kotlin/js/translate/callTranslator/FunctionCallCases.kt b/js/js.translator/src/org/jetbrains/kotlin/js/translate/callTranslator/FunctionCallCases.kt
index 5450d35d333..c35dfe04dd8 100644
--- a/js/js.translator/src/org/jetbrains/kotlin/js/translate/callTranslator/FunctionCallCases.kt
+++ b/js/js.translator/src/org/jetbrains/kotlin/js/translate/callTranslator/FunctionCallCases.kt
@@ -282,7 +282,8 @@ object DynamicOperatorCallCase : FunctionCallCase() {
             }
             is JetPostfixExpression -> {
                 // TODO drop hack with ":JsExpression" when KT-5569 will be fixed
-                JsPostfixOperation(OperatorTable.getUnaryOperator(operationToken), dispatchReceiver): JsExpression
+                @Suppress("USELESS_CAST")
+                (JsPostfixOperation(OperatorTable.getUnaryOperator(operationToken), dispatchReceiver) as JsExpression)
             }
             else -> unsupported("Unsupported callElement type: ${callElement.javaClass}, callElement: $callElement, callInfo: $this")
         }
diff --git a/js/js.translator/src/org/jetbrains/kotlin/js/translate/declaration/DelegationTranslator.kt b/js/js.translator/src/org/jetbrains/kotlin/js/translate/declaration/DelegationTranslator.kt
index 0b9b61b24ac..9a0c0aeadae 100644
--- a/js/js.translator/src/org/jetbrains/kotlin/js/translate/declaration/DelegationTranslator.kt
+++ b/js/js.translator/src/org/jetbrains/kotlin/js/translate/declaration/DelegationTranslator.kt
@@ -36,7 +36,7 @@ import org.jetbrains.kotlin.psi.JetClassOrObject
 import org.jetbrains.kotlin.psi.JetDelegationSpecifier
 import org.jetbrains.kotlin.psi.JetDelegatorByExpressionSpecifier
 import org.jetbrains.kotlin.resolve.DescriptorUtils
-import java.util.HashMap
+import java.util.*
 
 public class DelegationTranslator(
         private val classDeclaration: JetClassOrObject,
@@ -116,13 +116,13 @@ public class DelegationTranslator(
             val delegateRefName = context().getScopeForDescriptor(getterDescriptor).declareName(delegateName)
             val delegateRef = JsNameRef(delegateRefName, JsLiteral.THIS)
 
-            val returnExpression = if (DescriptorUtils.isExtension(descriptor)) {
+            val returnExpression: JsExpression = if (DescriptorUtils.isExtension(descriptor)) { // TODO remove explicit type specification after resolving KT-5569
                 val getterName = context().getNameForDescriptor(getterDescriptor)
                 val receiver = Namer.getReceiverParameterName()
                 JsInvocation(JsNameRef(getterName, delegateRef), JsNameRef(receiver))
             }
             else {
-                JsNameRef(propertyName, delegateRef): JsExpression // TODO remove explicit type specification after resolving KT-5569
+                JsNameRef(propertyName, delegateRef)
             }
 
             val jsFunction = simpleReturnFunction(context().getScopeForDescriptor(getterDescriptor.getContainingDeclaration()), returnExpression)