FINALLY FIXED THE PROBLEM - was using set instead of set_single, so it set it's child as well, causing the type loop. Also, the binding replace child evaluated the parameters first, changing t's parent before t->parent->replace_child happened

stdlib/tree.krak

@@ -1,5 +1,7 @@
 import mem
 import vec
+import io:*
+import str:*
 
 obj tree<T> (Object) {
     var data: T