There's one module I wrote that I use in a lot of my programs and for some reason, whenever I compile a program using this module with -O or -O2, make changes to the Main, and then recompile, I get the following error from ghc: Skipping Pattern ( Pattern.hs, Pattern.o ) failed to load interface for `Pattern': Could not find interface file for `Pattern' Failed to find interface decl for `Pattern.a' from module `Pattern' if I "ls Pattern.*" I get Pattern.hi, Pattern.hs and Pattern.o. In order to get it to compile correctly, I have to rm Pattern.o and then rerun ghc on the Main module. I've attached the Pattern.hs fyi. If anyone has any suggestions, please let me know. (btw, I'm using --make) Thanks! - Hal -- Hal Daume III "Computer science is no more about computers | hdaume@isi.edu than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume