Found the crash: need to register set_iterator_cls as a static root

src/runtime/set.cpp

@@ -17,6 +17,7 @@
 #include <sstream>
 
 #include "codegen/compvars.h"
+#include "gc/collector.h"
 #include "runtime/objmodel.h"
 
 namespace pyston {
@@ -214,6 +215,7 @@ void setupSet() {
                                new BoxedFunction(boxRTFunction((void*)setiteratorHasnext, BOXED_BOOL, 1, false)));
     set_iterator_cls->giveAttr("next", new BoxedFunction(boxRTFunction((void*)setiteratorNext, UNKNOWN, 1, false)));
     set_iterator_cls->freeze();
+    gc::registerStaticRootObj(set_iterator_cls);
 
     CLFunction* new_ = boxRTFunction((void*)setNew1, SET, 1, false);
     addRTFunction(new_, (void*)setNew2, SET, 2, false);

test/tests/gcj_2014_2_d.py

 # expected: fail
-# - crashes somewhere
+# - need to support closures
 
 import sys
 

test/tests/set.py

@@ -28,3 +28,6 @@ s.add(None)
 print len(s)
 
 print set([1])
+
+for i in set([1]):
+    print i