The document discusses the problem of copy-and-paste programming where not all instances of variables are changed leading to errors. It proposes two tools, CnP and CReN, to help detect and prevent such errors. CnP would track copy-pasted code and highlight inconsistencies based on the programmer's intentions. CReN would detect inconsistencies in identifier renaming, naming patterns, and types. Related work on clone detection, tracking, and error detection is also discussed.