Introduce new type checker.

core/util.runtime/src/org/jetbrains/kotlin/utils/functions.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2015 JetBrains s.r.o.
+ * Copyright 2010-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,6 +31,7 @@ private val ALWAYS_NULL: (Any?) -> Any? = { null }
 fun <T, R: Any> alwaysNull(): (T) -> R? = ALWAYS_NULL as (T) -> R?
 
 val DO_NOTHING: (Any?) -> Unit = { }
+val DO_NOTHING_2: (Any?, Any?) -> Unit = { x, y -> }
 val DO_NOTHING_3: (Any?, Any?, Any?) -> Unit = { x, y, z -> }
 
 fun <T> doNothing(): (T) -> Unit = DO_NOTHING