Let me point out that the haskell / GHC toolset is broad and deep and constantly being expanded, and also the most common causes of space leaks are becoming documented (the wiki and many stackoverflow threads. Tools:

ghc-vis, to visualize sharing: http://felsin9.de/nnis/ghc-vis/

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profilers and analysis of space/time behavior of data structures

http://www.haskell.org/ghc/docs/latest/html/users_guide/prof...

http://blog.ezyang.com/2011/05/space-leak-zoo/

http://lambdamaphone.blogspot.com/2011/02/automatic-asymptot...

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and, sort of a stacktrace:

http://jpmoresmau.blogspot.com/2012/10/using-ghci-history-in...

https://plus.google.com/u/0/107890464054636586545/posts/CfKE...

http://hackage.haskell.org/trac/ghc/wiki/Status/May12

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(not related to time/space reasoning, but a common pea under the mattress): in 7.4 you don't need top level "let" in GHCi

http://www.haskell.org/ghc/docs/7.4.1/html/users_guide/inter...