diff --git a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/highlighter/HtmlKotlinVisitor.kt b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/highlighter/HtmlKotlinVisitor.kt
index e923d6682b9..2f5fe8d53f2 100644
--- a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/highlighter/HtmlKotlinVisitor.kt
+++ b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/highlighter/HtmlKotlinVisitor.kt
@@ -14,7 +14,7 @@ class HtmlKotlinVisitor: JetTreeVisitor<StringBuilder>() {
             visitJetFile(file, data)
         }
     }
-    public override fun visitJetFile(file: JetFile?, data: StringBuilder?): Void? {
+    public override fun visitJetFile(file: JetFile, data: StringBuilder?): Void? {
         if (file != null) {
             println("============ Jet File ${file.getName()}")
             acceptChildren(file, data)
@@ -23,12 +23,12 @@ class HtmlKotlinVisitor: JetTreeVisitor<StringBuilder>() {
     }
 
 
-    public override fun visitClassObject(classObject: JetClassObject?, data: StringBuilder?): Void? {
+    public override fun visitClassObject(classObject: JetClassObject, data: StringBuilder?): Void? {
         println("============ class $classObject data $data")
         return super.visitClassObject(classObject, data)
     }
 
-    public override fun visitClass(klass: JetClass?, data: StringBuilder?): Void? {
+    public override fun visitClass(klass: JetClass, data: StringBuilder?): Void? {
         println("============ class $klass")
         if (klass != null) {
             acceptChildren(klass, data)
@@ -39,13 +39,13 @@ class HtmlKotlinVisitor: JetTreeVisitor<StringBuilder>() {
     }
 
 
-    public override fun visitClassBody(classBody: JetClassBody?, data: StringBuilder?): Void? {
+    public override fun visitClassBody(classBody: JetClassBody, data: StringBuilder?): Void? {
         println("============ class body $classBody data $data")
         return super.visitClassBody(classBody, data)
     }
 
 
-    public override fun visitFunctionType(fnType: JetFunctionType?, data: StringBuilder?): Void? {
+    public override fun visitFunctionType(fnType: JetFunctionType, data: StringBuilder?): Void? {
         println("======================= function Type $fnType")
         return super.visitFunctionType(fnType, data)
     }