Hi, while writing some code transformation code, I found out that in many implementations of RBProgramNode & co. the #copy message makes a sort of deep copy, copying also it's child nodes. However, it does NOT sets it's parent to the copy, so for copied nodes, following does not hold: someNode children anyOne parent == someNode This seems to br wrong to me. In other implementations I can simply use #deepCopy and works fine, but I cannot do this in Pharo because #deepCopy fails. The reason is that in Pharo RBProgramNodes are infested with OpalCompiler stuff which apparently keeps BlockClosures which cannot be deep-copied. The tree I'm trying to copy is obtained using BlockClosure>>sourceNode. Question: Is there a way how to copy the parse tree with parents set properly? If not, I'm inclined to fix #copy so it sets parent node properly If that's not desirable for one reason or another, no problem, I'll do it differently (but not-so-nicely :-) Best, Jan