applied pull request with thanks https://github.com/JetBrains/kotlin/pull/46

libraries/stdlib/src/kotlin/JUtil.kt

@@ -172,6 +172,14 @@ val <T> List<T>.last : T?
       return if (s > 0) this.get(s - 1) else null
     }
 
+/**
+ * Returns the index of the last item in the list or -1 if the list is empty
+ *
+ * @includeFunctionBody ../../test/ListTest.kt lastIndex
+ */
+val <T> List<T>.lastIndex : Int
+    get() = this.size - 1
+
 /**
  * Returns the first item in the list
  *

libraries/stdlib/test/ListTest.kt

@@ -1,5 +1,6 @@
 package test.collections
 
+import java.util.ArrayList
 import kotlin.test.*
 import org.junit.Test as test
 
@@ -36,4 +37,12 @@ class ListTest {
         }
         assertEquals(data.size(), index)
     }
+
+    test fun lastIndex() {
+        val emptyData = ArrayList<String>()
+        val data = arrayList("foo", "bar")
+
+        assertEquals(-1, emptyData.lastIndex)
+        assertEquals(1, data.lastIndex)
+    }
 }