diff --git a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/lib/LibraryUtil.kt b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/lib/LibraryUtil.kt
index b9f69987445..5483ac7fd59 100644
--- a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/lib/LibraryUtil.kt
+++ b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/lib/LibraryUtil.kt
@@ -5,5 +5,5 @@ package org.jetbrains.kotlin.idea.debugger.sequence.lib
  * @author Vitaliy.Bibaev
  */
 object LibraryUtil {
-    val KOTLIN_LANGUAGE_ID = "kotlin"
+    const val KOTLIN_LANGUAGE_ID = "kotlin"
 }
\ No newline at end of file
diff --git a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/lib/sequence/KotlinSequencesSupport.kt b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/lib/sequence/KotlinSequencesSupport.kt
index fc16327db7b..cd01c23f4e1 100644
--- a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/lib/sequence/KotlinSequencesSupport.kt
+++ b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/lib/sequence/KotlinSequencesSupport.kt
@@ -63,7 +63,7 @@ class KotlinSequencesSupport : LibrarySupportBase() {
     private fun sortedOperations(vararg names: String): Array<IntermediateOperation> =
         names.map { SortedOperation(it) }.toTypedArray()
 
-    private class FilterIsInstanceOperationHandler() : IntermediateOperationBase(
+    private class FilterIsInstanceOperationHandler : IntermediateOperationBase(
         "filterIsInstance", ::FilterIsInstanceHandler,
         SimplePeekCallTraceInterpreter(), FilteredMapResolver()
     )
diff --git a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/psi/impl/KotlinChainTransformerImpl.kt b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/psi/impl/KotlinChainTransformerImpl.kt
index 257fad58099..24107a1ad13 100644
--- a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/psi/impl/KotlinChainTransformerImpl.kt
+++ b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/psi/impl/KotlinChainTransformerImpl.kt
@@ -29,11 +29,10 @@ class KotlinChainTransformerImpl(private val typeExtractor: CallTypeExtractor) :
         val intermediateCalls = mutableListOf<IntermediateStreamCall>()
         for (call in callChain.subList(0, callChain.size - 1)) {
             val (typeBefore, typeAfter) = typeExtractor.extractIntermediateCallTypes(call)
-            intermediateCalls += IntermediateStreamCallImpl(call.callName(),
-                                                            call.valueArguments.map { createCallArgument(call, it) },
-                                                            typeBefore,
-                                                            typeAfter,
-                                                            call.textRange
+            intermediateCalls += IntermediateStreamCallImpl(
+                call.callName(), call.valueArguments.map { createCallArgument(call, it) },
+                typeBefore, typeAfter,
+                call.textRange
             )
         }
 
diff --git a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/psi/impl/TerminatedChainBuilder.kt b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/psi/impl/TerminatedChainBuilder.kt
index 88bc4b81464..886b5ca878a 100644
--- a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/psi/impl/TerminatedChainBuilder.kt
+++ b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/psi/impl/TerminatedChainBuilder.kt
@@ -46,7 +46,7 @@ open class TerminatedChainBuilder(
 
             val parentCall = expression.previousCall()
             if (parentCall is KtCallExpression && callChecker.isStreamCall(parentCall)) {
-                myPreviousCalls.put(expression, parentCall)
+                myPreviousCalls[expression] = parentCall
                 updateCallTree(parentCall)
             }
         }
@@ -64,7 +64,7 @@ open class TerminatedChainBuilder(
                     current = myPreviousCalls[current]
                 }
 
-                Collections.reverse(chain)
+                chain.reverse()
                 chains.add(chain)
             }
 
diff --git a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/trace/impl/handler/collections/FilterCallHandler.kt b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/trace/impl/handler/collections/FilterCallHandler.kt
index 348af30acef..a4eba5e820f 100644
--- a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/trace/impl/handler/collections/FilterCallHandler.kt
+++ b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/trace/impl/handler/collections/FilterCallHandler.kt
@@ -17,10 +17,10 @@ import org.jetbrains.kotlin.idea.debugger.sequence.trace.impl.handler.withArgs
  */
 class FilterCallHandler : BothSemanticsHandler {
     private companion object {
-        val VALUES_ARRAY_NAME = "objectsInPredicate"
-        val PREDICATE_RESULT_ARRAY_NAME = "filteringResults"
+        const val VALUES_ARRAY_NAME = "objectsInPredicate"
+        const val PREDICATE_RESULT_ARRAY_NAME = "filteringResults"
 
-        fun oldPredicateVariableName(order: Int): String = "filterPredicate" + order
+        fun oldPredicateVariableName(order: Int): String = "filterPredicate$order"
     }
 
     override fun variablesDeclaration(call: StreamCall, order: Int, dsl: Dsl): List<VariableDeclaration> {
diff --git a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/trace/impl/handler/sequence/KotlinDistinctByHandler.kt b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/trace/impl/handler/sequence/KotlinDistinctByHandler.kt
index 3a1274a0e5e..6ff6a33d1f4 100644
--- a/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/trace/impl/handler/sequence/KotlinDistinctByHandler.kt
+++ b/idea/idea-jvm/src/org/jetbrains/kotlin/idea/debugger/sequence/trace/impl/handler/sequence/KotlinDistinctByHandler.kt
@@ -18,8 +18,8 @@ import org.jetbrains.kotlin.idea.debugger.sequence.trace.dsl.KotlinTypes
  */
 class KotlinDistinctByHandler(callNumber: Int, private val call: IntermediateStreamCall, dsl: Dsl) : HandlerBase.Intermediate(dsl) {
     private companion object {
-        val KEY_EXTRACTOR_VARIABLE_PREFIX = "keyExtractor"
-        val TRANSITIONS_ARRAY_NAME = "transitionsArray"
+        const val KEY_EXTRACTOR_VARIABLE_PREFIX = "keyExtractor"
+        const val TRANSITIONS_ARRAY_NAME = "transitionsArray"
     }
 
     private val peekHandler = PeekTraceHandler(callNumber, "distinctBy", call.typeBefore, call.typeAfter, dsl)
diff --git a/idea/tests/org/jetbrains/kotlin/idea/debugger/sequence/KotlinPsiChainBuilderTestCase.kt b/idea/tests/org/jetbrains/kotlin/idea/debugger/sequence/KotlinPsiChainBuilderTestCase.kt
index 8a1c6ac12f9..cb1f764f220 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/debugger/sequence/KotlinPsiChainBuilderTestCase.kt
+++ b/idea/tests/org/jetbrains/kotlin/idea/debugger/sequence/KotlinPsiChainBuilderTestCase.kt
@@ -43,7 +43,7 @@ abstract class KotlinPsiChainBuilderTestCase(private val relativePath: String) :
         doKotlinTearDown(LightPlatformTestCase.getProject(), { super.tearDown() })
     }
 
-    override final fun getRelativeTestPath(): String = relativePath
+    final override fun getRelativeTestPath(): String = relativePath
 
     override fun setUp() {
         super.setUp()
@@ -106,7 +106,7 @@ abstract class KotlinPsiChainBuilderTestCase(private val relativePath: String) :
             checkChains(chains)
         }
 
-        protected fun checkChains(chains: MutableList<StreamChain>) {
+        private fun checkChains(chains: MutableList<StreamChain>) {
             TestCase.assertFalse(chains.isEmpty())
         }
     }
diff --git a/idea/tests/org/jetbrains/kotlin/idea/debugger/sequence/exec/KotlinTraceTestCase.kt b/idea/tests/org/jetbrains/kotlin/idea/debugger/sequence/exec/KotlinTraceTestCase.kt
index aaca96b236f..330aca4ee69 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/debugger/sequence/exec/KotlinTraceTestCase.kt
+++ b/idea/tests/org/jetbrains/kotlin/idea/debugger/sequence/exec/KotlinTraceTestCase.kt
@@ -49,7 +49,7 @@ abstract class KotlinTraceTestCase : KotlinDebuggerTestBase() {
     fun doTest(filePath: String) = doTestImpl(filePath)
 
     override fun createDebugProcess(path: String) {
-        val filePath = Paths.get(path);
+        val filePath = Paths.get(path)
         FileBasedIndex.getInstance().requestReindex(VfsUtil.findFileByIoFile(filePath.toFile(), true)!!)
         val packagePath = StringUtil.substringAfterLast(filePath.parent.toAbsolutePath().toString(), "src${File.separatorChar}")
                 ?: throw AssertionError("test data must be placed into test app project in 'src' directory")
@@ -145,7 +145,7 @@ abstract class KotlinTraceTestCase : KotlinDebuggerTestBase() {
         }, testRootDisposable)
     }
 
-    protected fun getPositionResolver(): DebuggerPositionResolver {
+    private fun getPositionResolver(): DebuggerPositionResolver {
         return DebuggerPositionResolverImpl()
     }
 
@@ -169,7 +169,7 @@ abstract class KotlinTraceTestCase : KotlinDebuggerTestBase() {
         traceChecker.checkResolvedChain(resolvedTrace)
     }
 
-    protected fun handleResultValue(result: Value?) {
+    private fun handleResultValue(result: Value?) {
     }
 
     private fun getResultInterpreter(): TraceResultInterpreter {
@@ -196,7 +196,7 @@ abstract class KotlinTraceTestCase : KotlinDebuggerTestBase() {
 
             fun byIndex(index: Int): ChainSelector {
                 return object : ChainSelector {
-                    override fun select(chains: List<StreamChain>): StreamChain = chains.get(index)
+                    override fun select(chains: List<StreamChain>): StreamChain = chains[index]
                 }
             }
         }