Look at those Huskell retards and laugh

However, this comes with the caveats of using WriterT [a], which is that it will leak space like crazy for a large assembly computation (even if you don't log anything!).

This is wrong.

*Main Control.Monad> take 2 . flip evalState 0 . execWriterT $ forever (byte 4)
[4,4]

Also, when complied with -O2 then

main = print . flip evalState 0 . execWriterT $ forever (byte 4)

appears to run in constant memory.

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Huh. I guess that works because the whole stack is lazy. However, if you make the base State monad strict then WriterT leaks space:

>>> import Control.Monad.Trans.Writer
>>> import Control.Monad.Trans.State.Strict
>>> import Control.Monad.Trans.Class
>>> import Control.Monad
>>> runStateT (execWriterT (forever (lift (put 1)))) 0 -- Leaks space

More laughs from Haskell idiots:

Looking for a purely functional replacement for mutable vectors, but all are at least 100 times slower. Any alternative?