It seems to want to allocate huge amounts of memory. It iven semms to overflow:
Prelude> import qualified Data.Text as T
Prelude T> :set -XOverloadedStrings
Prelude T> T.toLower (T.replicate 200000 "0")
"<interactive>: internal error: Unable to commit -1604321280 bytes of memory
(GHC version 8.2.2 for x86_64_unknown_linux)
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
It seems to want to allocate huge amounts of memory. It iven semms to overflow: