[Haskell-cafe] problems with trace

After I load the following into ghci and call main I expect to see "norm" in the output 3 times as I have called it 3 times but it only shows once. Why? traceBug.hs --------------- {-# OPTIONS_GHC -Wall #-} import Debug.Trace (trace) norm :: [Int] -> [Int] norm = trace ("norm") id main :: IO () main = do print $ norm [2] print $ norm [2] print $ norm [3] --------------------- ghci session % ghci traceBug.hs Loaded package environment from /Users/gcolpitts/.ghc/x86_64-darwin-9.8.2/environments/default GHCi, version 9.8.2: https://www.haskell.org/ghc/ :? for help [1 of 2] Compiling Main ( traceBug.hs, interpreted ) Ok, one module loaded. ghci> main norm [2] [2] [3] ghci>