Hi, I have problems with memory leaks and can't find out how to avoid them. I tried to reduce sample to demonstrate the following problems: 1) when compiled without -O2 option, it iconsumes 1582MB (!) total memory 2) when compiled with -O2 option it terminates with "out of memory" Actually I don't understand the reasons, particulary why GC can't collect already processed objects g,...,n (see code below)? I would appreciate very much any help with this situation. Thanks! module Main where import qualified Data.Map as M len = 15*1024*1024 lst from = take len $ zip [from..] [0..] g = M.size $ M.fromList $ lst 0 h = M.size $ M.fromList $ lst 0 i = M.size $ M.fromList $ lst 0 j = M.size $ M.fromList $ lst 0 k = M.size $ M.fromList $ lst 0 l = M.size $ M.fromList $ lst 0 m = M.size $ M.fromList $ lst 0 n = M.size $ M.fromList $ lst 0 main = do mapM_ print [g,h,i,j,k,l,m,n]