diff --git a/js/js.libraries/src/core/javautil.kt b/js/js.libraries/src/core/javautil.kt
index 68407ba14a1..0e00c6df9a9 100644
--- a/js/js.libraries/src/core/javautil.kt
+++ b/js/js.libraries/src/core/javautil.kt
@@ -68,11 +68,11 @@ public trait Collection<erased E> : java.lang.Iterable<E> {
 }
 
 library
-public abstract open class AbstractCollection<erased E> : Collection<E> {
+public abstract open class AbstractCollection<erased E>() : Collection<E> {
 }
 
 library
-public abstract open class AbstractList<erased E> : AbstractCollection<E>, List<E> {
+public abstract open class AbstractList<erased E>() : AbstractCollection<E>(), List<E> {
     public override fun isEmpty() : Boolean = js.noImpl
     public override fun contains(o : Any?) : Boolean = js.noImpl
     public override fun iterator() : Iterator<E> = js.noImpl
diff --git a/js/js.libraries/src/stdlib/browser.kt b/js/js.libraries/src/stdlib/browser.kt
index 69c07e1aa5a..c62023de748 100644
--- a/js/js.libraries/src/stdlib/browser.kt
+++ b/js/js.libraries/src/stdlib/browser.kt
@@ -7,5 +7,5 @@ import org.w3c.dom.Document
 /**
  * Provides access to the current active browsers DOM for the currently visible page.
  */
-native("document") var document: Document
+native("document") var document: Document = null!!