diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/psi/CallKey.java b/compiler/frontend/src/org/jetbrains/jet/lang/psi/CallKey.java
index 61e4b7ecd47..9c278d5ff3e 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/psi/CallKey.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/psi/CallKey.java
@@ -16,6 +16,7 @@
 
 package org.jetbrains.jet.lang.psi;
 
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.lang.psi.Call.CallType;
 
 /**
@@ -30,7 +31,8 @@ public class CallKey {
         this.element = element;
     }
 
-    public static CallKey create(CallType callType, JetExpression element) {
+    @NotNull
+    public static CallKey create(@NotNull CallType callType, @NotNull JetExpression element) {
         return new CallKey(callType, element);
     }