added a demonstration of how Kotlin currently handles nullable collections on for loops - by throwing NPEs

testlib/test/language/NullableCollectionsTest.kt

@@ -0,0 +1,20 @@
+package test.language
+
+import junit.framework.TestCase
+import java.util.Collection
+import stdhack.test.*
+
+class NullableCollectionsTest : TestCase() {
+
+    fun testIterateOverNullCollectionsThrowsNPE() {
+        val c: Collection<String>? = null
+
+        // TODO currently this will throw a NPE
+        // should it either be a compile error or handle nulls gracefully?
+        failsWith<NullPointerException> {
+            for (e in c) {
+                println("Hey got $e")
+            }
+        }
+    }
+}